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NIST SP 800-126r4: Technical Specification for the Security Content Automation Protocol (SCAP): SCAP Version 1.4

Dragos Prisaca (NIST); Stephen Quinn (NIST); Jack Vander Pol (NIWC Atlantic); Daniel Harris (NIWC Atlantic) · National Institute of Standards and Technology (NIST)

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NIST Special Publication 800 NIST SP 800-126r4

Technical Specification for the Security Content Automation Protocol (SCAP) SCAP Version 1.4 Dragos Prisaca Stephen D. Quinn Jack Vander Pol Daniel K. Harris This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.800-126r4

NIST Special Publication 800 NIST SP 800-126r4

Technical Specification for the Security Content Automation Protocol (SCAP) SCAP Version 1.4 Dragos Prisaca Stephen D. Quinn

Computer Security Division Information Technology Laboratory

Jack Vander Pol Daniel K. Harris

Naval Information Warfare Center (NIWC) Atlantic

This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.800-126r4

June 2026

U.S. Department of Commerce Howard Lutnick, Secretary of Commerce National Institute of Standards and Technology Arvind Raman, NIST Director and Under Secretary of Commerce for Standards and Technology

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

Certain equipment, instruments, software, or materials, commercial or non-commercial, are identified in this paper in order to specify the experimental procedure adequately. Such identification does not imply recommendation or endorsement of any product or service by NIST, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. There may be references in this publication to other publications currently under development by NIST in accordance with its assigned statutory responsibilities. The information in this publication, including concepts and methodologies, may be used by federal agencies even before the completion of such companion publications. Thus, until each publication is completed, current requirements, guidelines, and procedures, where they exist, remain operative. For planning and transition purposes, federal agencies may wish to closely follow the development of these new publications by NIST. Organizations are encouraged to review all draft publications during public comment periods and provide feedback to NIST. Many NIST cybersecurity publications, other than the ones noted above, are available at https://csrc.nist.gov/publications. Authority This publication has been developed by NIST in accordance with its statutory responsibilities under the Federal Information Security Modernization Act (FISMA) of 2014, 44 U.S.C. § 3551 et seq., Public Law (P.L.) 113-283. NIST is responsible for developing information security standards and guidelines, including minimum requirements for federal information systems, but such standards and guidelines shall not apply to national security systems without the express approval of appropriate federal officials exercising policy authority over such systems. This guideline is consistent with the requirements of the Office of Management and Budget (OMB) Circular A-130. Nothing in this publication should be taken to contradict the standards and guidelines made mandatory and binding on federal agencies by the Secretary of Commerce under statutory authority. Nor should these guidelines be interpreted as altering or superseding the existing authorities of the Secretary of Commerce, Director of the OMB, or any other federal official. This publication may be used by nongovernmental organizations on a voluntary basis and is not subject to copyright in the United States. Attribution would, however, be appreciated by NIST. NIST Technical Series Policies Copyright, Use, and Licensing Statements NIST Technical Series Publication Identifier Syntax Publication History Approved by the NIST Editorial Review Board on 2026-04-23 How to Cite this NIST Technical Series Publication Prisaca D, Quinn SD, Vander Pol J, Harris DK (2026) Technical Specification for the Security Content Automation Protocol (SCAP): SCAP Version 1.4. (National Institute of Standards and Technology, Gaithersburg, MD), NIST Special Publication (SP) NIST SP 800-126r4. https://doi.org/10.6028/NIST.SP.800-126r4 Author ORCID iDs Dragos Prisaca: 0009-0007-7361-8433 Stephen D. Quinn: 0000-0003-1436-684X

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

Contact Information scap@nist.gov National Institute of Standards and Technology Attn: Computer Security Division, Information Technology Laboratory 100 Bureau Drive (Mail Stop 8930) Gaithersburg, MD 20899-8930 Additional Information Additional information about this publication is available at https://csrc.nist.gov/pubs/sp/800/126/r4/final, including related content, potential updates, and document history. All comments are subject to release under the Freedom of Information Act (FOIA).

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

Abstract The Security Content Automation Protocol (SCAP) is a suite of specifications that standardize the format and nomenclature by which software flaw and security configuration information is communicated, both to machines and humans. This publication, along with its annex (NIST Special Publication 800-126Ar4) and a set of schemas, collectively define the technical composition of SCAP version 1.4 in terms of its component specifications, their interrelationships and interoperation, and the requirements for SCAP content. Keywords checklists; patch verification; security automation; security checklists; security configuration; Security Content Automation Protocol (SCAP); software flaws; vulnerabilities. Reports on Computer Systems Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the Nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analyses to advance the development and productive use of information technology. ITL’s responsibilities include the development of management, administrative, technical, and physical standards and guidelines for the cost-effective security and privacy of other than national security-related information in federal information systems. The Special Publication 800-series reports on ITL’s research, guidelines, and outreach efforts in information system security, and its collaborative activities with industry, government, and academic organizations.

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Technical Specification for SCAP Version 1.4

Patent Disclosure Notice NOTICE: ITL has requested that holders of patent claims whose use may be required for compliance with the guidance or requirements of this publication disclose such patent claims to ITL. However, holders of patents are not obligated to respond to ITL calls for patents and ITL has not undertaken a patent search in order to identify which, if any, patents may apply to this publication. As of the date of publication and following call(s) for the identification of patent claims whose use may be required for compliance with the guidance or requirements of this publication, no such patent claims have been identified to ITL. No representation is made or implied by ITL that licenses are not required to avoid patent infringement in the use of this publication.

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Technical Specification for SCAP Version 1.4

Table of Contents Executive Summary............................................................................................................................1 1. Introduction ...................................................................................................................................2

2. SCAP 1.4 Definition ........................................................................................................................5

3. SCAP Content Requirements and Recommendations .......................................................................9 3.1.1. Source Data Stream Data Model ................................................................................................ 12 3.1.2. Source Data Stream Collection Validation ................................................................................. 18 3.1.2.1. Informative Notes ................................................................................................................. 19 3.1.3. Globally Unique Identifiers ......................................................................................................... 19 3.2.1. General ....................................................................................................................................... 20 3.2.2. The <xccdf:Benchmark> Element ............................................................................................... 20 3.2.3. The <xccdf:Profile> Element....................................................................................................... 21 3.2.4. The <xccdf:Rule> Element .......................................................................................................... 21 3.2.4.1. The <xccdf:ident> Element ................................................................................................... 21 3.2.4.2. The <xccdf:check> Element .................................................................................................. 22 3.2.4.3. Use of a Patches Up-To-Date Rule ........................................................................................ 24 3.2.4.4. CVSS and CCSS Scores ........................................................................................................... 25 3.2.5. The <xccdf:Value> Element ........................................................................................................ 26 3.2.6. The <xccdf:Group> Element ....................................................................................................... 27

3.8.1. Supported CVSS Versions ........................................................................................................... 33 3.8.2. Version Precedence .................................................................................................................... 33 iii

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3.8.3. Metric Groups............................................................................................................................. 34 3.8.4. Known Limitation in XCCDF ........................................................................................................ 34

3.10.1. Signature Location .................................................................................................................... 34 3.10.2. Signature Representation......................................................................................................... 35 3.10.3. Signature Requirements ........................................................................................................... 35 3.10.4. Key Information ........................................................................................................................ 36 4. SCAP Content Processing Requirements and Recommendations ....................................................37

4.3.1. CPE Applicability Processing ....................................................................................................... 38 4.3.2. Checking System Usage .............................................................................................................. 38 4.4.1. The Component Reports ............................................................................................................ 40 4.4.2. The Target Identification ............................................................................................................ 41 4.4.3. The Source Data Stream ............................................................................................................. 41 4.4.4. The Relationships ....................................................................................................................... 42 4.5.1. Assigning Identifiers to Rule Results .......................................................................................... 46 4.5.2. Mapping OVAL Results to XCCDF Results ................................................................................... 46

4.8.1. Signature Location ...................................................................................................................... 50 4.8.2. Signature Representation........................................................................................................... 50 4.8.3. Signature Requirements ............................................................................................................. 50 4.8.4. Key information .......................................................................................................................... 50 4.8.5. Countersigning ........................................................................................................................... 51 5. Source Data Stream Content Requirements for Use Cases .............................................................52

Appendix A. Security Considerations ................................................................................................55

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Technical Specification for SCAP Version 1.4

Appendix B. List of Symbols, Abbreviations, and Acronyms ...............................................................56 Appendix C. Glossary .......................................................................................................................58 Appendix D. Normative References ..................................................................................................60 Appendix E. Change Log ...................................................................................................................61

List of Tables Table 1. Conventional XML mappings .................................................................................................4 Table 2. ds:data-stream-collection....................................................................................................13 Table 3. ds:data-stream....................................................................................................................14 Table 4. ds:dictionaries ....................................................................................................................14 Table 5. ds:checklists........................................................................................................................15 Table 6. ds:checks ............................................................................................................................15 Table 7. ds:extended-components ....................................................................................................15 Table 8. ds:component-ref ...............................................................................................................15 Table 9. cat:catalog ..........................................................................................................................16 Table 10. cat:uri ...............................................................................................................................16 Table 11. cat:rewriteURI...................................................................................................................17 Table 12. ds:component ...................................................................................................................17 Table 13. ds:extended-component ...................................................................................................17 Table 14. SCAP source data stream component document elements .................................................18 Table 15. Element identifier format convention ................................................................................19 Table 16. Use of Dublin Core terms in <xccdf:metadata> ...................................................................21 Table 17. <xccdf:Rule> and <xccdf:ident> element values..................................................................22 Table 18. XCCDF-OVAL data export matching constraints ..................................................................27 Table 19. SCAP result data stream component document elements...................................................40 Table 20. Asset identification fields to populate................................................................................41 Table 21. ARF relationships ..............................................................................................................42 Table 22. XCCDF fact descriptions .....................................................................................................44 Table 23. Deriving XCCDF check results from OVAL definition results .................................................47 Table 24. Specification locations .......................................................................................................60

List of Figures Fig. 1. Notional SCAP data stream collection .....................................................................................10 Fig. 2. SCAP data stream ...................................................................................................................11 Fig. 3. Sample ARF report structure ..................................................................................................42 v

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Technical Specification for SCAP Version 1.4

Acknowledgments The authors wish to thank all individuals who have contributed to this and prior revisions of SP 800-126. Specifically, the authors thank the co-authors of the previous revision: Harold Booth of NIST, David Waltermire formerly from NIST, and Karen Kent of the Trusted Cyber Annex. The authors also offer a special thanks to the contributors to this revision, including Robert Byers, Jim Foti, Bob Gendler, Blair Heiserman, Gopi Katwala, and Isabel Van Wyk from NIST and Greg Witte from Palydin LLC.

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Technical Specification for SCAP Version 1.4

Executive Summary The Security Content Automation Protocol (SCAP) is a suite of specifications that standardize the format and nomenclature by which security configuration information is communicated to both machines and humans. 1 SCAP is a multi-purpose framework of specifications that support automated configuration, vulnerability and patch checking, technical and managerial control compliance activities, and security measurement. Goals for the development of SCAP include standardizing system security management, promoting the interoperability of security products, and fostering the use of standard expressions of security content. Security configuration in SCAP format is curated and managed by the NIST National Checklist Program (NCP), which is described in NIST Special Publication (SP) 800-70r5 (Revision 5). This document, its annex [SP800-126Ar4], and a set of schemas collectively define the technical composition of SCAP version 1.4 in terms of its component specifications and requirements. The technical specification for SCAP describes the conventions for ensuring the consistent and accurate exchange of SCAP-conformant content and the ability to reliably use the content with SCAP-conformant products. Organizations that develop SCAP 1.4-based content or products should adhere to the following recommendations: •

Follow the requirements listed in this document, its annex, and the associated component specifications and set of schemas. Organizations should ensure that their implementation and use of SCAP 1.4 complies with the requirements detailed in each component specification, this document, its annex, and the set of schemas. If requirements conflict between component specifications, this document will provide clarification. If a component specification conflicts with this document, the requirements in this document take precedence. If a component specification or this document conflicts with the annex, the requirements in the annex take precedence. If a specification and a schema conflict, the requirements in the specification take precedence.

•

When creating SCAP content, adhere to the conventions specified in this document and its annex. Security products and checklist authors assemble content from SCAP data repositories to create SCAP-conformant security guidance. Organizations that produce SCAP content to be shared between tools should adhere to the conventions described in this specification to ensure the highest degree of interoperability.

1 Products that implement SCAP can also be used to support non-security use cases, such as configuration management, software inventory,

and malware hunting.

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1. Introduction 1.1. Purpose and Scope This document, its annex [SP800-126A], and a set of schemas collectively provide the technical specification for version 1.4 of the Security Content Automation Protocol (SCAP). SCAP (pronounced /EHS-kap/) consists of a suite of specifications for standardizing the format and nomenclature by which software flaw and security configuration information is communicated to both machines and humans. This document defines requirements for creating and processing SCAP source content that build on the requirements defined within the individual SCAP component specifications. Each new requirement pertains to either using multiple component specifications together or further constraining one of the individual component specifications. 2 To extend the contents of this document, [SP800-126A] has been created as an annex to specify additional entities that may be used in SCAP 1.4-conformant content creation and processing. It provides: •

Particular minor version updates to SCAP 1.4 component specifications

•

Particular Open Vulnerability and Assessment Language (OVAL) platform schema versions

The scope of this document and its annex is limited to SCAP version 1.4. Other versions of SCAP and its component specifications are not addressed in these documents. Future versions of SCAP will be defined in distinct revisions of this document and its annex, each clearly labeled with a document revision number and the appropriate SCAP version number. 1.2. Audience This document is intended for: •

Content authors and editors who seek to ensure that the SCAP source content they produce operates correctly, consistently, and reliably in SCAP products

•

Software developers and system integrators who seek to create, use, or exchange SCAP content in their products or service offerings

1.3. Document Structure The remainder of this document is organized into the following major sections and appendices: •

Section 2 provides the high-level requirements for claiming conformance with the SCAP 1.4 specification.

2 Refer to the individual component specifications to see their requirements.

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•

Section 3 details the requirements and recommendations for SCAP content syntax, structure, and development.

•

Section 4 defines SCAP content processing requirements and recommendations.

•

Section 5 provides additional content requirements and recommendations for particular use cases.

•

Appendix A gives an overview of major security considerations for SCAP implementation.

•

Appendix B provides an acronym and abbreviation list.

•

Appendix C provides a glossary of selected terms used in this document.

•

Appendix D lists references and other resources related to SCAP 1.4.

•

Appendix E provides a log of significant changes to previous versions of this specification.

1.4. Document Conventions In this document, the capitalized terms “MUST,” “MUST NOT,” “REQUIRED,” “SHALL,” “SHALL NOT,” “SHOULD,” “SHOULD NOT,” “RECOMMENDED,” “MAY,” and “OPTIONAL” are to be interpreted as described in Request for Comment (RFC) 2119 [RFC2119]. When these words appear in lowercase (e.g., “should,” “may”), they are not intended to be interpreted as RFC 2119 key words. Italicized single terms are defined and listed in Appendix C. Some of the requirements and conventions used in this document reference Extensible Markup Language (XML) content [XMLS]. These references come in two forms: inline and indented. An example of an inline reference is: A <cpe2_dict:cpe-item> may contain <cpe2_dict:check> elements that reference OVAL definitions. In this example, the notation <cpe2_dict:cpe-item> can be replaced by a more verbose equivalent: “The XML element whose qualified name is cpe2_dict:cpe-item.” An example of an indented reference is: References to OVAL definitions are expressed using the following format: <cpe2_dict:check system= "http://oval.mitre.org/XMLSchema/oval-definitions-5" href="Oval_URL">[Oval_inventory_definition_id] </cpe2_dict:check>

When describing XML attributes within this document, the general convention is to reference the attribute and its associated element, including the namespace alias: @attributeName for the <prefix:localName>

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Indented references are intended to represent the form of actual XML content. Indented references represent literal content by the use of a fixed-length font and parametric (i.e., freely replaceable) content by the use of italics. Square brackets ‘[]’ are used to designate optional content. Thus, “[Oval_inventory_definition_id]” designates optional content. Both inline and indented forms use qualified names to refer to specific XML elements. A qualified name associates a named element with a namespace. The namespace identifies the XML model, and the XML schema is a definition and implementation of that model. A qualified name declares this schema-to-element association using the format “prefix:element-name.” The association of prefix to namespace is defined in the metadata of an XML document and varies from document to document. In this specification, the conventional mappings listed in Table 1 are used. Table 1. Conventional XML mappings 3 Prefix

Namespace

Schema

ai arf arf-rel

http://scap.nist.gov/schema/asset-identification/1.1 http://scap.nist.gov/schema/asset-reporting-format/1.1 http://scap.nist.gov/specifications/arf/vocabulary/relationships/ 1.0# urn:oasis:names:tc:entity:xmlns:xml:catalog http://scap.nist.gov/schema/scap/constructs/1.4 http://scap.nist.gov/schema/cpe-extension/2.3

Asset Identification ARF ARF relationships

cat con cpe-dictext cpe2 cpe2-dict cve

http://cpe.mitre.org/language/2.0 http://cpe.mitre.org/dictionary/2.0 http://scap.nist.gov/schema/vulnerability/0.4

dc ds

http://purl.org/dc/elements/1.1/ http://scap.nist.gov/schema/scap/source/1.2

http://scap.nist.gov/schema/xml-dsig/1.0

nvd ocil oval oval-def oval-res oval-sc oval-var sch xccdf xlink xml xs xxxx-def, xxxx-sc

http://scap.nist.gov/schema/feed/vulnerability/2.0 http://scap.nist.gov/schema/ocil/2.0 http://oval.mitre.org/XMLSchema/oval-common-5 http://oval.mitre.org/XMLSchema/oval-definitions-5 http://oval.mitre.org/XMLSchema/oval-results-5 http://oval.mitre.org/XMLSchema/oval-system-characteristics-5 http://oval.mitre.org/XMLSchema/oval-variables-5 http://purl.oclc.org/dsdl/schematron http://checklists.nist.gov/xccdf/1.2 http://www.w3.org/1999/xlink http://www.w3.org/XML/1998/namespace http://www.w3.org/2001/XMLSchema See [SP800-126A] for the mappings for OVAL definition and system characteristic schemas.

XML Catalog SCAP Constructs CPE Dictionary 2.3 schema extension Embedded CPE references CPE dictionaries NVD/CVE data feed elements and attributes Simple Dublin Core elements SCAP source data stream collection Security automation digital signature extensions Base schema for NVD data feeds OCIL elements and attributes OVAL elements and attributes OVAL definitions OVAL results OVAL system characteristics OVAL variable requirements Schematron used for validation XCCDF policy documents XML Linking Language Common XML attributes XML schema OVAL elements and attributes specific to an OS, Hardware, or Application type

3 Namespace values are literal XML namespace identifiers for use in SCAP content and are not necessarily navigable web references

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2. SCAP 1.4 Definition In general, SCAP version 1.4 is comprised of 12 component specifications in five categories: 1. Languages. The SCAP languages provide standard vocabularies and conventions for expressing security policies, technical check mechanisms, and assessment results. The SCAP language specifications are the Extensible Configuration Checklist Description Format (XCCDF), Open Vulnerability and Assessment Language (OVAL), and Open Checklist Interactive Language (OCIL). 2. Reporting formats. SCAP reporting provides the necessary constructs to express collected information in standardized formats. The SCAP reporting format specifications are Asset Reporting Format (ARF) and Asset Identification. Although Asset Identification is not explicitly a reporting format, SCAP uses it as a key component in identifying the assets that reports relate to. 3. Identification schemes. The SCAP identification schemes provide a means to identify key concepts, such as software products, vulnerabilities, and configuration items that use standardized identifier formats. They also provide a means to associate individual identifiers with additional data pertaining to the subject of the identifier. The SCAP identification scheme specifications are the Common Platform Enumeration (CPE), Common Configuration Enumeration (CCE), and Common Vulnerabilities and Exposures (CVE). 4. Measurement and scoring systems. In SCAP, this refers to evaluating the specific characteristics of a security weakness (e.g., software vulnerabilities and security configuration issues) and generating a score that reflects their relative severity. The SCAP measurement and scoring system specifications are the Common Vulnerability Scoring System (CVSS) and Common Configuration Scoring System (CCSS). 5. Integrity. An SCAP integrity specification helps preserve the integrity of SCAP content and results. The Trust Model for Security Automation Data (TMSAD) is the SCAP integrity specification. More specifically, the five categories for the component specifications included in SCAP 1.4 are: 1. Languages o Extensible Configuration Checklist Description Format (XCCDF) 1.2, a language for authoring security checklists/benchmarks and for reporting results of evaluating them [XCCDF] o Open Vulnerability and Assessment Language (OVAL) 5.12, a language for representing system configuration information, assessing machine states, and reporting assessment results [OVAL] 4

4 See the SCAP 1.4 annex document [SP800-126A] for the OVAL component specification (core schema) versions and platform schema versions

that are supported by SCAP 1.4.

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o Open Checklist Interactive Language (OCIL) 2.0, a language for representing checks that collect information from people or existing data stores made by other data collection efforts [OCIL] 2. Reporting formats o Asset Reporting Format (ARF) 1.1, a format for expressing the transport format of information about assets and the relationships between assets and reports [ARF] o Asset Identification 1.1, a format for uniquely identifying assets based on known identifiers and/or known information about the assets [AI] 3. Identification schemes o Common Platform Enumeration (CPE) 2.3, a nomenclature and dictionary of hardware, operating systems, and applications [CPE] o Common Configuration Enumeration (CCE) 5, a nomenclature and dictionary of software security configurations [CCE] o Common Vulnerabilities and Exposures (CVE), a nomenclature and dictionary of security-related software flaws 5 [CVE] 4. Measurement and scoring systems o Common Vulnerability Scoring System (CVSS) v3.1 and v4.0, open frameworks for measuring the relative severity of software flaw vulnerabilities. CVSS v4.0 is the preferred version for newly authored SCAP content; CVSS v3.1 is the minimum supported version. See Sec. 3.8 for version-precedence requirements [CVSS-3.1] [CVSS-4.0]. o Common Configuration Scoring System (CCSS) 1.0, a system for measuring the relative severity of system security configuration issues [CCSS] 5. Integrity o Trust Model for Security Automation Data (TMSAD) 1.0, a specification for using digital signatures in a common trust model applied to other security automation specifications [TMSAD] All references to these specifications within this document are to the minor version numbers listed in the annex. 6 These versions represent the baseline of interoperability for all SCAP products that support SCAP 1.4. Support for older versions of these specifications may be included in an SCAP 1.4 product, but support for legacy SCAP versions should not interfere with the product’s ability to address the requirements in this specification and the annex. In some cases, support for specific legacy versions of these specifications is required by this specification, such as the requirements discussed in Sec. 4.1.

5 CVE does not have a version number.

6 Section 1 of the SCAP 1.4 annex document [SP800-126A] provides definitions for the terms “major version” and “minor version.”

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Combinations of these specifications can be used together for particular functions, such as security configuration checking. These functions, known as SCAP use cases, are ways in which a product can use SCAP. The collective XML content used for a use case is called an SCAP data stream, which is a specific instantiation of SCAP content. There are two types of SCAP data streams: an SCAP source data stream holds the input content, and an SCAP result data stream holds the output content. The major elements of a data stream (e.g., an XCCDF benchmark, a set of OVAL definitions) are referred to as stream components. Products and source content may want to claim conformance to one or more of the SCAP use cases (see Sec. 5) for a variety of reasons. For example, a product may want to assert that it uses SCAP content properly and can interoperate with other products using valid SCAP content. Another example is a policy mandating that an organization use SCAP source content to perform vulnerability assessments and other security operations. This section provides the high-level requirements that a product or source content must meet for conformance with the SCAP 1.4 specification. Such products and source content are referred to as SCAP-conformant. Most of the requirements listed in this section reference other sections that fully define the requirements. If requirements are in conflict between component specifications, this document will provide clarification. If a component specification conflicts with this document, the requirements in this document SHALL take precedence. This document will be republished with errata as needed, and the errata SHALL take precedence over the original document content. The requirements in [SP800-126A] SHALL take precedence over conflicting requirements in this document or the component specifications. If an SCAP specification or component specification and a schema are in conflict, the requirements in the specification SHALL take precedence over all conflicting requirements in the schema. 2.1. Product Conformance There are two types of SCAP-conformant products: content producers and content consumers. Content producers generate SCAP source data streams. Content consumers accept existing SCAP source data streams, process them, and (when required by the supported use cases) produce SCAP result data streams. Products that claim conformance with the SCAP 1.4 specification SHALL comply with the following requirements: 1. Adhere to component specifications. Adhere to the requirements in each applicable SCAP component specification, both for each component that the product implements and for each component required to implement the selected SCAP use cases. The authoritative references for component specifications are listed in [SP800‑126A]. 2. Implement errata. Adhere to the requirements in the errata for this document and SP 800‑126A that are in effect as of the product’s release date.

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3. Producer requirements. For content producers, generate SCAP source data streams that are (a) XML well‑formed, (b) schema-valid per the applicable component specifications, and (c) conformant to the source content conformance requirements in Sec. 2.2 and the use case requirements in Sec. 5. 4. Consumer requirements. For content consumers, accept and process SCAP source data streams and, when required by the supported use cases, generate SCAP result data streams that are XML well‑formed and schema‑valid. Content consumers SHALL follow all processing requirements in Sec. 4 for each selected SCAP component specification and each component specification required to implement the selected SCAP use cases and SHALL detect and report non‑conformant input. 5. Conformance claim. Make an explicit claim of conformance to this specification in documentation provided to end users. The claim SHALL identify at least (a) this specification and version (SCAP 1.4), (b) the implemented roles (e.g., producer, consumer), (c) the supported SCAP use cases (Sec. 5), and (d) the implemented SCAP component specifications and versions. 2.2. Source Content Conformance Source content (i.e., source data streams) that claim conformance with the SCAP 1.4 specification SHALL comply with the following requirements: 1. Component specifications. Adhere to the requirements specified in each applicable SCAP component specification. This includes both the component specifications explicitly selected for the content and any additional component specifications required to support the selected SCAP use cases. Authoritative references for each specification are provided in [SP800-126A]. 2. Errata. Adhere to the requirements published in errata for this document and SP 800-126A. In the event of a conflict, the errata SHALL take precedence. 3. Syntax, structure, and use cases. Follow all syntax, structural, and design requirements defined in Sec. 3 for each applicable component specification. In addition, follow all use case-specific requirements defined in Sec. 5.

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Technical Specification for SCAP Version 1.4

3. SCAP Content Requirements and Recommendations This section defines the SCAP 1.4 content syntax, structure, and development requirements and recommendations for SCAP-conformant content and products. Organizations are encouraged to adopt the optional recommendations to promote stronger interoperability and greater content consistency. The first part of the section discusses SCAP source data streams. The middle of the section groups requirements and recommendations by specification: XCCDF, OVAL, OCIL, CPE, CCE, CVE, CVSS, and CCSS, in that order. Finally, the last part of the section discusses applying XML digital signatures to source data streams. 3.1. SCAP Source Data Stream This subsection discusses SCAP source data streams only; SCAP result data streams are discussed in Sec. 4.4 as part of the requirements for SCAP processing. An SCAP source data stream collection is composed of SCAP data streams and SCAP source components.7 The components section contains an unbounded number of SCAP source components, each consisting of data expressed using one or more of the SCAP specifications. The data streams section contains one or more source data streams, each of which references the source components that compose the data stream. This model allows source components to be reused across multiple data streams. Many data streams are allowed in a data stream collection to allow for the grouping of related or similar source data streams. Figure 1 shows a possible relationship between data stream collections, data streams, and components.

7 See https://csrc.nist.gov/Projects/security-content-automation-protocol/scap-releases/scap-1-4 for a sample of an SCAP source data stream

collection and its sections.

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Data Stream Collection xccdf1 xccdf2

Data Stream 1

oval1 oval2 oval3 Data Stream 2

cpe dict1 cpe dict2

data streams

components

Fig. 1. Notional SCAP data stream collection

In Fig. 1, data stream 1 points to xccdf1, xccdf2, oval1, oval3, cpe dict1, and cpe dict2. Data stream 2 points to xccdf2, oval2, oval3, and cpe dict2. Each data stream is a collection of links to the components it references, represented as <ds:component-ref>. Each component-ref encapsulates the information required to allow the content consumer to connect the components that are embedded in content with the data stream component that should be used. Content authors MAY place components in any order. For example, some authors might choose to place dictionary components first to help optimize data stream parsing. Links in a <ds:component-ref> element serve two purposes: to indicate which component is being referred to and to provide a map to associate references within a component to other links within the data stream. The latter allows a data stream to define context for each component’s references within the bounds of the data stream’s own set of links. Figure 2 provides a conceptual example that illustrates how a data stream is constructed.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

datastream checklists

checks

dictionaries

component-ref: scap_id_cref_ref2

component-ref: scap_id_cref_ref3

component-ref: scap_id_cref_ref1 Mapping

Mapping To: From:

To: From:

#scap_id_cref_ref3 sample-oval-comp

#scap_id_cref_ref3 dict-oval-comp

Link: scap_id_comp_xccdf1

Link: scap_id_comp_oval1

Link: scap_id_comp_dict1

component: scap_id_comp_xccdf1 XCCDF Checklist References: sample-oval-comp

component: scap_id_comp_oval1 OVAL Definitions

component: scap_id_comp_dict1 CPE Dictionary References: dict-oval-comp

Fig. 2. SCAP data stream

The following XML is a stripped-down example of the source data stream depicted in Fig. 2. 1 <ds:data-stream-collection id="scap_datastream_collection_1" schematronversion="1.4"> 2 <ds:data-stream id="scap_id_datastream_ds1" scap-version="1.4" usecase="CONFIGURATION"> 3 <ds:dictionaries> 4 <ds:component-ref id="scap_id_cref_ref1" xlink:href="#scap_id_comp_dict1"> 5 <cat:catalog> 6 <cat:uri name="dict-oval-comp" uri="#scap_id_cref_ref3"/> 7 </cat:catalog> 8 </ds:component-ref> 9 </ds:dictionaries> 10 <ds:checklists> 11 <ds:component-ref id="scap_id_cref_ref2" xlink:href="#scap_id_comp_xccdf1"> 12 <cat:catalog> 13 <cat:uri name="sample-oval-comp" uri="#scap_id_cref_ref3"/> 14 </cat:catalog> 15 </ds:component-ref> 16 </ds:checklists> 17 <ds:checks> 18 <ds:component-ref id="scap_id_cref_ref3" xlink:href="#scap_id_comp_oval1"/> 19 </ds:checks> 20 </ds:data-stream> 21 <ds:component id="scap_id_comp_xccdf1" timestamp="2016-01-22T14:00:00"> 22 <xccdf:Benchmark id="xccdf_gov.nist_benchmark_SCAP13" style=" SCAP_1.4"> 23 … 24 <xccdf:Rule id="xccdf_gov.nist_rule_id-001"> 25 <xccdf:check system="http://oval.mitre.org/XMLSchema/oval-definitions-5"> 26 <xccdf:check-content-ref href="sample-oval-comp" name="oval:gov.nist:def:1"/> 27 </xccdf:check> 28 </xccdf:Rule> 29 </xccdf:Benchmark> 30 </ds:component> 31 <ds:component id="scap_id_comp_oval1" timestamp="2016-01-22T14:00:00"> 32 <oval-def:oval_definitions>...</oval-def:oval_definitions> 33 </ds:component> 34 <ds:component id="scap_id_comp_dict1" timestamp="2016-01-22T14:00:00"> 35 <cpe2-dict:cpe-list> 36 <cpe2-dict:cpe-item name="cpe:/a:oracle:database_server:11.1.0.6.0::enterprise">

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

37 <cpe2-dict:check href="dict-oval-comp" 38 system="http://oval.mitre.org/XMLSchema/oval-definitions-5”> 39 oval:gov.nist:def:2</cpe2-dict:check> 40 <cpe-dict-ext:cpe23-item 41 name="cpe:2.3:a:oracle:database_server:11.1.0.6.0:-:-:-:enterprise:-:-:"/> 42 </cpe2-dict:cpe-item> 43 </cpe2-dict:cpe-list> 44 </ds:component> 45 </ds:data-stream-collection>

In Fig. 2, the data stream links to three components. The OVAL component scap_id_comp_oval1 (see XML lines 31-33 above) does not reference external content, so there are no mappings captured for it. The XCCDF component (scap_id_comp_xccdf1) (see XML lines 21-30) and the CPE Dictionary component (scap_id_comp_dict1) (see XML lines 34-44) reference other components (e.g., scap_id_cref_ref3). When referencing components within the example data stream, a mapping indicates that when scap_id_comp_xccdf1 references “sample-oval-comp,” the content is found through the link to the component identified as “scap_id_comp_oval1” (see XML lines 26, 13, and 18). Similarly, when the scap_id_comp_dict1 component references “dict-oval-comp,” the component reference is resolved through the link to the component identified as “scap_id_comp_oval1” (see XML lines 37, 6, and 18). This approach associates SCAP components within a data stream at the SCAP logical level, allowing components to be reused across data streams within the same data stream collection. This reuse can be accomplished irrespective of how references are made within a given component. The design of the SCAP source data stream is important for the following reasons: 1. Individual components may be developed outside of an SCAP data stream, where linking to other components is not necessarily known when the component is created. 2. The SCAP source data stream creates links between different components that were not necessarily designed to reference each other. For example, XCCDF was not designed to reference a particular checking system; it can reference OVAL, OCIL, and other checking systems. 3. The logical link mapping in the data stream places a layer of capability within the data stream to control the dereferencing of URIs within components, creating a complete solution related to bundling components. 4. The SCAP source data stream format is intended to be easily adaptable for use in future communication models (e.g., web services, transport protocols, tasking mechanisms). 5. The SCAP source data stream format supports more comprehensive validation of component content, including interrelationships between components. 3.1.1. Source Data Stream Data Model The tables in this section formalize the SCAP source data stream data model. The tables contain requirements and SHALL be interpreted as follows:

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

•

The “Element Name” field indicates the name for the XML element being described. Each element name has a namespace prefix indicating the namespace to which the element belongs. See Table 1 for a mapping of namespace prefixes to namespaces.

•

The “Element Definition” field indicates the prose description of the element. The definition field MAY contain key words, as indicated in [RFC2119].

•

The “Properties” field is broken into four subfields: 1. The “Name” column indicates the name of a property that MAY, SHOULD, or SHALL be included in the described element, in accordance with the cardinality indicated in the “Count” column and any [RFC2119] requirement words in the “Property Definition” column. 2. The “Type” column indicates the REQUIRED data type for the value of the property. There are two categories of types: literal and element. A literal type indicates the type of literal as defined in [XMLS]. An element type references the name of another element that ultimately defines that property. 3. The “Count” column indicates the cardinality of the property within the element. The property SHALL be included in the element in accordance with the cardinality. If a range is given, and “n” is the upper bound of the range, then the upper limit SHALL be unbounded. 4. The “Property Definition” column defines the property in the context of the element. The definition MAY contain key words, as indicated in [RFC2119]. Table 2. ds:data-stream-collection

Element Name: ds:data-stream-collection Element Definition

The top-level element for an SCAP data stream collection. It contains the data streams, the components that comprise this data stream collection, and any data stream signatures.

Properties: Name

Type

Count

Property Definition

literal – ID

schematronversion data-stream

literal – token

element – ds:datastream element – ds:component element – ds:extendedcomponent element – dsig:Signature

1-n

The identifier for the data stream collection. This identifier SHALL be globally unique (see Sec. 3.1.3). The version of the SCAP Requirements Schematron schema to which the data stream collection conforms. An element that represents a single data stream collection (see Table 3).

component extendedcomponent Signature

1-n 0-n 0-n

An element that represents content expressed using an SCAP component specification (see Table 12). An element that holds non-SCAP components to enable extension (see Table 13). An XML digital signature element. Sections 3.10 and 4.8 define the requirements for this element.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4 Table 3. ds:data-stream

Element Name: ds:data-stream Element Definition

A data stream. This element contains the links to all of the components that comprise this data stream.

Properties Name

Type

Count

Property Definition

literal – ID

use-case

literal – token

scap-version

literal – token

timestamp

literal – dateTime element – ds:dictionaries element – ds:checklists element – ds:checks element – ds:extendedcomponents

0-1

The identifier for the data stream. This identifier SHALL be globally unique (see Sec. 3.1.3). The use case represented by the data stream. The value SHALL be one of the following: CONFIGURATION, VULNERABILITY, INVENTORY, or OTHER. The value selected SHALL indicate which type of content is being represented, as defined in Sec. 5. The value “OTHER” is for content that does not correspond to a specific use case. This content SHALL be valid according to the requirements defined in Sec. 3 and 4. The targeted SCAP version. The value SHALL be 1.4, 1.3, or 1.2. The value SHALL indicate which version of SCAP the content is conformant with. 1.4 SHALL be specified to be conformant with this version of SCAP. The date and time when this data stream was created.

0-1

Links to dictionary components (see Table 4).

0-1

Links to checklist components (see Table 5).

Links to check components (see Table 6).

0-1

Links to non-standard components (see Table 7). See Section 4.2 for information on processing this element.

dictionaries checklists checks extendedcomponents

Table 4. ds:dictionaries Element Name: ds:dictionaries Element Definition

A container element that holds references to one or more dictionary components.

Properties Name

Type

Count

Property Definition

component-ref

element – componentref

1-n

SHALL contain a reference to a dictionary component (a component containing CPE dictionary content).

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4 Table 5. ds:checklists

Element Name: ds:checklists Element Definition

A container element that holds references to one or more checklists.

Properties Name

Type

Count

Property Definition

component-ref

element – componentref

1-n

SHALL contain a reference to a checklist component (i.e., a component containing an <xccdf:Benchmark> or an <xccdf:Tailoring> element). Table 6. ds:checks

Element Name: ds:checks Element Definition

A container element that holds references to one or more check components.

Properties Name

Type

Count

Property Definition

component-ref

element – componentref

1-n

SHALL contain a reference to a check component (i.e., a component containing check content). See Sec. 3.2.4.2 for information on SCAPchecking system support and requirements. Table 7. ds:extended-components

Element Name: ds:extended-components Element Definition

A container element that holds references to one or more extended components for the SCAP data stream, including non-standard components.

Properties Name

Type

Count

Property Definition

component-ref

element – componentref

1-n

SHALL contain a reference to a non-standard component (a <ds:extended-component> element ). See Table 13. Table 8. ds:component-ref

Element Name: ds:component-ref Element Definition

An element that encapsulates the information necessary to link to a component within the data stream collection or to external content, which gives context to the reference. This is a simple XLink [XLINK].

Properties Name

Type

Count

Property Definition

literal - ID

type

literal – xlink:type

0-1

href

literal – xlink:href

The identifier for the reference. This identifier SHALL be globally unique (see Sec. 3.1.3). The type of XLink represented. The <ds:component-ref> is constrained to a simple XLink, so the value of this field SHALL be ‘simple’ if specified. A URI to the target component (either local to the data stream collection or remote). When referencing a local component, the URI SHALL be in the form ‘#’ + componentId (e.g., “#component1”). When referencing external content, the URI SHALL be in the form of scheme:[//[user:password@]host[:port]][/]path[?query][#fragment], as

NIST SP 800-126r4 June 2026

catalog

element – cat:catalog

Technical Specification for SCAP Version 1.4

0-1

specified in [RFC3986], and SHALL dereference to an XML stream that includes the SCAP source data stream collection and the target component (e.g., “file:Data_Stream_Collection.xml#scap_gov.nist_comp_1”). An XML Catalog that defines the mapping between external URI links in the component being referenced by this <ds:componentref> and where those URIs should map to within the context of this data stream. See Table 9. Table 9. cat:catalog

Element Name: cat:catalog Element Definition

A catalog element defined by the OASIS XML Catalog specification [XMLCAT]. Within an SCAP source data stream, this element SHALL contain one or more <cat:uri> and/or <cat:rewriteURI> elements, and it SHALL NOT contain any other elements or attributes. Refer to Sec. 7 of [XMLCAT] for information on determining which catalog entry to apply.

Properties Name

Type

Count

Property Definition

uri

element – cat:uri

Maps a reference in the enclosing <ds:component-ref> element’s component to some other <ds:component-ref> element that SHALL be used to resolve the reference. See Table 10.

rewriteURI

element – cat:rewrit eURI

0-n (at least 1 of this or rewriteURI SHALL be provided) 0-n (at least 1 of this or uri SHALL be provided)

A rewriteURI element defined by the OASIS XML Catalog specification [XMLCAT]. Within an SCAP source data stream, this element can be used to rewrite the beginning of a reference in the enclosing <ds:component-ref> element’s component to some other <ds:component-ref> element that SHALL be used to resolve the reference. See Table 11. Table 10. cat:uri

Element Name: cat:uri Element Definition

A URI element defined by the OASIS XML Catalog specification [XMLCAT]. Within an SCAP source data stream, this element maps a reference in the enclosing <ds:component-ref> element's component to some other <ds:component-ref> element that SHALL be used to resolve the reference. A <cat:uri> element SHALL have a @name attribute and a @uri attribute.

Properties Name

Type

Count

Property Definition

name

literal – xs:anyURI

uri

literal – xs:anyURI

The @name attribute is the source of the mapping and SHALL contain a URI that matches a “referenced URI” in the data stream component referenced by the <ds:component-ref> that holds this element. The “referenced URI” is a URI entry defined within the model used within the data stream component. The @uri attribute is the destination of the mapping and SHALL be populated with the value “#” + @id of a <ds:component-ref>. When resolving the URI in the @name attribute, the <ds:component-ref> pointed to by the @uri attribute SHALL be used.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4 Table 11. cat:rewriteURI

Element Name: cat: rewriteURI Element Definition

A rewriteURI element defined by the OASIS XML Catalog specification [XMLCAT]. Within an SCAP source data stream, this element can be used to rewrite the beginning of a reference in the enclosing <ds:component-ref> element’s component to some other <ds:componentref> element that SHALL be used to resolve the reference. A <cat: rewriteURI> element SHALL have a @uriStartString attribute and a @rewritePrefix attribute specified. See [XMLCAT] for more details.

Properties Name

Type

Count

Property Definition

uriStartString

literal – xs:anyURI

rewritePrefix

literal – xs:anyURI

The @uriStartString attribute SHALL be populated with the start of a URI of an external link specified within the component referenced by this element’s enclosing <ds:component-ref> element that is to be replaced. The @rewritePrefix attribute SHALL be populated with a string that will replace the matched @uriStartString value. The resulting URI SHALL be used to resolve the link. Table 12. ds:component

Element Name: ds:component Element Definition

A container for a single component. The types of components are defined in Sec. 3.1.2.

Properties Name

Type

Count

Property Definition

literal – ID

timestamp

literal – dateTime

The identifier for the component. This identifier SHALL be globally unique (see Sec. 3.1.3). Indicates when the <ds:component> was created or last updated. Table 13. ds:extended-component

Element Name: ds:extended-component Element Definition

This element holds content that does not fit within the other defined component types described in Table 12. Authors SHOULD use this element as an extension point to capture content that is not captured in a regular component. The content of this element SHALL be an XML element in a namespace other than the SCAP source data stream namespace. Linking through a <ds:extended-component> element SHALL make the data stream non-conformant with SCAP.

Properties Name

Type

Count

Property Definition

literal – ID

timestamp

literal – dateTime

The identifier for the component. This identifier SHALL be globally unique (see Sec. 3.1.3). Indicates when the <ds:extended-component> was created or last updated.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

3.1.2. Source Data Stream Collection Validation The SCAP source data stream collection SHALL validate against the XML schema representation for the source data stream and all associated Schematron schemas. The SCAP components referenced by each <ds:component> and <ds:extended-component> element SHALL validate against the corresponding component schema and its embedded Schematron rules. All of the SCAP-related schemas are referenced at https://csrc.nist.gov/Projects/security-contentautomation-protocol/scap-releases/scap-1-4. See Sec. 2 in [SP800-126A] for a list of SCAP component schema and Schematron schema locations. These XML and Schematron schemas will be updated if any errors are found. If the old schema links change, updated links will be provided in the annex as errors are corrected. Each SCAP source data stream component SHALL use one of the elements specified in Table 14 as its document element. Table 14. SCAP source data stream component document elements Component XCCDF Benchmark XCCDF Tailoring OVAL OCIL CPE Dictionary

Document Element <xccdf:Benchmark> <xccdf:Tailoring>

<oval-def:oval_definitions> <ocil:ocil>

<cpe2-dict:cpe-list>

SCAP source data stream components SHOULD NOT use any constructs that are deprecated in its associated specification. While Sec. 4.1 requires that products support deprecated constructs, these constructs should be avoided to minimize the impact to content use when the constructs are removed from future revisions of the associated specifications. Single data streams in a data stream collection SHALL NOT reference any component in the collection more than once. If applicable, each component SHALL validate against its associated Schematron schema. For the SCAP source data stream collection, it SHALL validate against the version of the SCAP Schematron rules as specified on the <ds:data-stream-collection> element’s @schematron-version attribute, and it SHOULD also validate against the latest Schematron rules. NIST provides and maintains a set of Schematron rules to check well-formed SCAP content. The Schematron schemas for the SCAP specification and its applicable component specifications are located at https://csrc.nist.gov/Projects/security-content-automationprotocol/scap-releases/scap-1-4. Source content SHOULD pass all Schematron assertions in the Schematron rule files. When creating source content, failed assertions with a “WARNING” or “INFO” flag MAY be disregarded if the assertion discovers an issue in the content that is justifiable and expected based on the needs of the content author. When executing source content, all failed assertions with a “WARNING” or “INFO” flag SHALL be disregarded. The Schematron schemas are interpretations of the specifications, and the implementations of their rules are subject to change. Whenever a change is made to a Schematron schema used for this SCAP version, the SCAP Schematron change log document will be updated, and the new

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

Schematron schema will be posted. The latest Schematron schema SHOULD be used in place of any earlier versions. If the latest file is unavailable, the version specified on the <ds:datastream-collection> element’s @schematron-version attribute SHALL be used instead. 3.1.2.1. Informative Notes •

Validation tooling: NIST has provided an SCAP Content Validation Tool to assist with checking that SCAP source and result content is well-formed, cross-references resolve, and required values are present. It can report errors and warnings in XML and HTML formats. Use of this or any particular tool is not required for conformance. The tool’s availability, feature set, and maintenance are not guaranteed and may change over time. Products and content authors MAY employ any equivalent validation tool that implements the requirements in this document and the associated component specifications.

•

Schematron rules: NIST has published Schematron rules to assist content authors and implementers in checking for conditions that are not enforced by XML Schema, such as structural or semantic consistency across components. Following these rules is not required for conformance, and NIST does not guarantee their availability, accuracy, or maintenance over time. Content authors and product developers MAY employ these or equivalent rule sets as an additional quality-assurance mechanism.

3.1.3. Globally Unique Identifiers The elements listed in Table 15 have special conventions for the format of their identifiers (@id attribute). Table 15. Element identifier format convention Element

<ds:data-stream-collection> <ds:data-stream> <ds:component-ref> <ds:component> <ds:extended-component>

Identifier Format Convention

scap_namespace_collection_name scap_namespace_datastream_name scap_namespace_cref_name scap_namespace_comp_name scap_namespace_ecomp_name

Authors SHALL follow these conventions because they preserve the global uniqueness of the resulting identifiers. In Table 15, namespace contains a valid reverse-DNS-style string (limited to letters, numbers, periods, and the hyphen character) that is associated with the content author. Examples include “com.acme.finance” and “gov.tla.” These namespace strings MAY have any number of parts, and SCAP content consumers processing them SHALL treat them as caseinsensitive (e.g., com.ABC is considered identical to com.abc). The name in the format conventions SHALL be an NCName-compliant string [XMLS].

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

3.2. Extensible Configuration Checklist Description Format (XCCDF) This section lists requirements and recommendations for using the Extensible Configuration Checklist Description Format (XCCDF) to express an XCCDF benchmark or tailoring component of an SCAP source data stream (see Table 14). They are organized by the following categories: general, <xccdf:Benchmark>, <xccdf:Profile>, <xccdf:Rule>, <xccdf:Value>, and <xccdf:Group>. 3.2.1. General The @xml:base attribute SHALL NOT be allowed in XCCDF content. This attribute is not compatible with the SCAP data stream model. Descriptive information within XCCDF MAY be used by SCAP products to assist in selecting the appropriate SCAP data stream, ensure that the most recent or correct version of an XCCDF document is used, and provide additional information about the document. The following requirements and conventions apply to the <xccdf:Benchmark>, <xccdf:Profile>, <xccdf:Value>, <xccdf:Group>, and <xccdf:Rule> elements: 1. One or more instances of the <xccdf:title> element SHALL be provided. Each instance SHALL contain a text value that briefly indicates the purpose of the containing element. 2. One or more instances of the <xccdf:description> element SHALL be provided. Each instance SHALL contain a text value that describes the purpose of the containing element. XInclude elements SHALL NOT be included in XCCDF content [XINCLUDE]. All remaining OPTIONAL elements in the XCCDF schema MAY be included at the author’s discretion unless otherwise noted in this document. 3.2.2. The <xccdf:Benchmark> Element The following requirements and recommendations apply to the <xccdf:Benchmark> element: 1. The <xccdf:version> element and the @id attribute SHALL be used together to uniquely identify all revisions of a benchmark. a. Multiple revisions of a single benchmark SHOULD have the same @id attribute value and different <xccdf:version> element values so that someone who reviews the revisions can readily identify them as multiple versions of a single benchmark. b. Multiple revisions of a single benchmark SHOULD have <xccdf:version> element values that indicate the revision sequence so that the history of changes from the original benchmark can be determined.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

c. The @time attribute of the <xccdf:version> element SHOULD be used for a timestamp of when the benchmark was defined. 2. The @update attribute of the <xccdf:version> element SHOULD be used for a URI that specifies where updates to the benchmark can be obtained. 3. The <xccdf:Benchmark> element SHALL have an @xml:lang attribute. 4. The @style attribute SHOULD have the value “SCAP_1.4.” 5. The <xccdf:status> element SHALL indicate the current status of the benchmark document. The associated text value SHALL be “draft” for documents released in public draft state and “accepted” for documents that have been officially released by an organization. The @date attribute SHALL be populated with the date of the status change. Additional <xccdf:status> elements MAY be included to indicate historic status transitions. 6. The <xccdf:metadata> element SHALL be provided and SHALL, at minimum, contain the Dublin Core [DCES] terms from Table 16. If provided, additional Dublin Core terms SHALL follow the required terms within the element sequence. Table 16. Use of Dublin Core terms in <xccdf:metadata> Dublin Core Term <dc:creator> <dc:publisher> <dc:contributor> <dc:source>

Description of Use The person, organization, and/or service that created the benchmark. The person, organization, and/or service that published the benchmark. The person, organization, and/or service that contributed to the creation of the benchmark. An identifier that indicates the organizational context of the benchmark’s @id attribute. An organizationally specific URI SHOULD be used.

3.2.3. The <xccdf:Profile> Element As stated in the XCCDF specification, the use of an <xccdf:Profile> element is not required, even though SCAP content commonly uses it. Use of the <xccdf:set-complex-value> element within the <xccdf:Profile> element SHALL NOT be allowed. Use of complex values is disallowed because the behavior for mapping XCCDF complex values to OVAL variables is not defined. 3.2.4. The <xccdf:Rule> Element The following requirements and recommendations apply to the <xccdf:Rule> element. The topics they address are <xccdf:ident> elements, <xccdf:check> elements, patching upto-date rules, and CVSS and CCSS scores. 3.2.4.1. The <xccdf:ident> Element Each <xccdf:Rule> element SHALL include an <xccdf:ident> element that contains a CVE, CCE, or CPE identifier reference if an appropriate identifier exists. The meaning of the identifier 21

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

SHALL be consistent with the recommendation implemented by the <xccdf:Rule> element. The <xccdf:ident> element content SHALL match the corresponding CVE, CCE, or CPE identifier found in the associated OVAL definitions if the rule references an OVAL definition, if an appropriate identifier exists, and if that OVAL definition is the only input to the rule’s final result. When referencing a CVE, CCE, or CPE identifier, an <xccdf:Rule> element SHALL have a purpose consistent with one of the rows in Table 17. Table 17. <xccdf:Rule> and <xccdf:ident> element values Purpose of the <xccdf:Rule>

OVAL Definition Class

Identifier Type

Value for <xccdf:ident> @system attribute 8

Check compliance with a configuration setting Perform a software inventory check Check for a software flaw vulnerability

compliance inventory vulnerability

CCE CPE CVE

http://cce.mitre.org http://cpe.mitre.org http://cve.mitre.org

Based on the purpose of the <xccdf:Rule> element, the <xccdf:Rule> SHALL define its <xccdf:ident> element’s @system attribute using the corresponding value from Table 17. Also, if the <xccdf:Rule> element references an OVAL definition, it SHALL reference an OVAL definition of the specified class. Here is a partial example of a rule intended to check compliance with a configuration setting: <xccdf:Rule id="xccdf_gov.nist.fdcc.xp_value_AuditAccountLogonEvents"> … <xccdf:ident system="http://cce.mitre.org">CCE-3867-0</xccdf:ident> … </xccdf:Rule>

See Sec. 4.5.1 for information on the meaning of a “pass/fail” rule result relating to each of the identifier types in Table 17. All rules that contain CCE, CPE, or CVE entries in their <xccdf:ident> elements SHALL obey these meanings. As a result, such <xccdf:ident> elements SHALL only be included if the recommendation is identical to these associated meanings or if they have a @con:negate attribute (as described in Sec. 4.5.1) set to comply with the intended meaning (by default, @con:negate is set to false). In SCAP, an <xccdf:ident> element is not simply a reference to related material — it is a declaration of exact alignment with the described meanings. An <xccdf:ident> element referencing a CVE, CCE, or CPE identifier SHALL be ordered before other <xccdf:ident> elements referencing non-SCAP identifiers. Identifiers from previous revisions of CCE or CPE MAY also be specified following the SCAP identifiers. 3.2.4.2. The <xccdf:check> Element The following requirements and recommendations apply to the <xccdf:check> element:

8 The URI values in this column are used to identify the naming system being used and have a MITRE designation due to historic naming

conventions.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

1. The <xccdf:check-content> element SHALL NOT be used to embed check content directly into XCCDF content. 2. At least one <xccdf:check-content-ref> element SHALL be provided for each <xccdf:check> element. 3. When evaluating an <xccdf:check-content-ref> element within an <xccdf:check> element, its @href attribute SHALL contain a “#” and the @id of a <ds:component-ref> element or SHALL be resolved in the context of the XML Catalog specified as part of the <ds:component-ref> element that is referencing this benchmark. In either case, the @href attribute SHALL ultimately resolve to a <ds:component-ref> element in the data stream referencing the benchmark containing this <xccdf:check-content-ref> element. See Sec. 3.1.1 for additional information on <ds:component-ref> resolution. This version of SCAP supports the use of only OVAL and/or OCIL-checking systems in SCAPconformant content. Use of these checking systems SHALL be restricted as follows: 1. OVAL checking system i.

Use of the OVAL checking system SHALL be indicated by setting the <xccdf:check> element’s @system attribute to

http://oval.mitre.org/XMLSchema/oval-definitions-5.

ii.

The @href attribute in the <xccdf:check-content-ref> element SHALL reference an OVAL source data stream component using the <ds:componentref> approach defined above.

iii.

Use of the @name attribute in the <xccdf:check-content-ref> element is OPTIONAL. If present, it SHALL reference an OVAL definition in the designated OVAL source data stream component. Otherwise, see Sec. 4.5.2 for information on the use of the @multi-check attribute.

2. OCIL-checking system i.

OCIL questionnaires SHOULD NOT be used if OVAL can perform the same check correctly.

ii.

Use of the OCIL checking system SHALL be indicated by setting the <xccdf:check> element’s @system attribute to http://scap.nist.gov/schema/ocil/2.0.

iii.

The @href attribute in the <xccdf:check-content-ref> element SHALL reference an OCIL source data stream component using the <ds:componentref> approach defined above.

iv.

Use of the @name attribute in the <xccdf:check-content-ref> element is OPTIONAL. If present, it SHALL reference an OCIL questionnaire in the designated OCIL source data stream component. Otherwise, see Sec. 4.5.2 for information on the use of the @multi-check attribute.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

All requirements in Appendix B of NIST Interagency Report (IR) 7692, Specifications for the Open Checklist Interactive Language (OCIL) Version 2.0 [OCIL], SHALL be followed.

A checking system that is not supported by SCAP MAY be used in XCCDF content. There is no guarantee that an SCAP implementation will be capable of processing any additional checking system data used in this content. To ensure interoperability, SCAP has standardized the use of OVAL and OCIL-checking systems. Content containing the use of checking systems other than the OVAL and OCIL-checking systems SHALL NOT be considered well-formed with regard to SCAP. 3.2.4.3. Use of a Patches Up-To-Date Rule An OVAL source data stream component MAY be used to represent a series of checks to verify that patches have been installed. Historically, an XCCDF convention has been used to identify such a reference. An XCCDF benchmark MAY include a patches up-to-date rule that SHALL reference an OVAL source data stream component. When implementing a patches up-to-date XCCDF rule that checks for patches via numerous OVAL patch class definitions, the following approach SHALL be used: 1. The source data stream SHALL include the OVAL source data stream component referenced by the patches up-to-date rule, which contains one or more OVAL patch class definitions and MAY contain other class definitions. 2. The <xccdf:Rule> element that references an OVAL source data stream component SHALL have the @id attribute value of xccdf_NAMESPACE_rule_security_patches_up_to_date, where NAMESPACE is the reverse DNS format namespace associated with the content maintainer. 3. Each <xccdf:check-content-ref> element SHALL omit the @name attribute. 4. The @multi-check attribute of the <xccdf:check> element SHALL be set to “true.” This causes a separate <xccdf:rule-result> to be generated for each OVAL patch definition. See Sec. 4.5.2 for more information. Use of this approach allows for the individual OVAL patch definitions to be easily identified along with the XCCDF rule checking whether patches are up to date. The following example of a patches up-to-date rule references numerous OVAL patch class definitions: <xccdf:Rule id="xccdf_gov.nist.usgcb.win_rule_security_patches_up_to_date" selected="true"> <xccdf:title>Security Patches Up-To-Date</xccdf:title> <xccdf:description>Keep systems up to current patch levels</xccdf:description> <xccdf:check system="http://oval.mitre.org/XMLSchema/oval-definitions-5" multi-check="true"> <xccdf:check-content-ref href="scap-windows-patches"/>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

</xccdf:check> </xccdf:Rule>

When implementing a patches up-to-date XCCDF rule that checks for patches via a single OVAL patch class definition, the following approach SHALL be used: 1. The source data stream SHALL include the OVAL source data stream component referenced by the patches up-to-date rule, which contains one or more OVAL patch class definitions and MAY contain other class definitions. 2. The <xccdf:Rule> element that references an OVAL source data stream component SHALL have the @id attribute value of xccdf_NAMESPACE_rule_security_patches_up_to_date, where NAMESPACE is the reverse DNS format namespace associated with the content maintainer. 3. Each <xccdf:check-content-ref> element SHALL refer to the single OVAL definition performing the patches up-to-date check. 4. The @multi-check attribute of the <xccdf:check> element SHALL be set to “false,” which is the default value. Use of a single OVAL patch definition provides for easier content maintenance and makes it easy to identify both the XCCDF rule and the patch class definition used for checking whether patches are up to date. Here is a patches up-to-date rule example that references a single OVAL patch class definition: <xccdf:Rule id="xccdf_gov.nist.usgcb.win_rule_security_patches_up_to_date" selected="true"> <xccdf:title>Security Patches Up-To-Date</xccdf:title> <xccdf:description>Keep systems up to current patch levels</xccdf:description> <xccdf:check system="http://oval.mitre.org/XMLSchema/oval-definitions-5" multi-check="false"> <xccdf:check-content-ref href="scap-windows-patches" name="oval:gov.nist.usgcb.win.patch:def:10101"/> </xccdf:check> </xccdf:Rule>

3.2.4.4. CVSS and CCSS Scores SCAP 1.0 required the inclusion of static CVSS scores in XCCDF vulnerability-related rules. However, CVSS base scores sometimes change over time (e.g., when more information is available about a particular vulnerability), and CVSS temporal and environmental scores are intended to change to reflect current threats, security controls, and other factors. As a result, the practice of embedding CVSS scores in XCCDF content was no longer required starting with SCAP 1.1. During scoring, current CVSS scores acquired dynamically, such as from a data feed, SHOULD be used in place of the @weight attribute within XCCDF vulnerability-related rules. Section 3.8 contains additional requirements for CVSS usage. 25

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Technical Specification for SCAP Version 1.4

CCSS scores are more stable than CVSS scores, but they still may change over time. Accordingly, during scoring, current CCSS scores acquired dynamically, such as from a data feed, MAY be used in place of the @weight attribute within XCCDF configuration setting-related rules. Section 3.9 contains additional requirements for CCSS usage. For both the CVSS and CCSS cases, this specification encourages the use of data feeds that can be updated over time. The specifics around scoring provided in this and referenced sections are intended to prevent potential misuse of the XCCDF @weight attribute within an SCAP data stream. SCAP 1.4 supports CVSS v3.1 and CVSS v4.0 as defined in [CVSS-3.1] and [CVSS-4.0] respectively, and continues to recognize CVSS v3.0 [CVSS-3.0] and CVSS v2.0 [CVSS-2.0] as legacy versions for pre-existing vulnerability data only. When more than one CVSS score is available for a given vulnerability from an authoritative source (such as the NIST National Vulnerability Database CVE feed referenced in Sec. 3.7), SCAP-conformant products SHOULD apply the versionprecedence rule defined in Sec. 3.8 - that is, products SHOULD prefer a CVSS v4.0 score over a CVSS v3.1 score, SHOULD prefer a CVSS v3.1 score over a CVSS v3.0 score, and SHOULD prefer a CVSS v3.0 score over a CVSS v2.0 score. This further supports the use of updatable data feeds to provide current CVSS information. As acknowledged in prior revisions of this specification, XCCDF does not provide a means to indicate which CVSS version was used when calculating an XCCDF score; this is a recognized weakness in the XCCDF specification. As a result, tool developers are encouraged not to rely solely on the scoring information embedded in an SCAP checklist for downstream risk decisions, and SHOULD instead recompute or revalidate CVSS scores against the latest authoritative source at evaluation time. 3.2.5. The <xccdf:Value> Element Use of the <xccdf:source>, <xccdf:complex-value>, and <xccdf:complexdefault> elements within the <xccdf:Value> element SHALL NOT be allowed. Within the <xccdf:choices> element of the <xccdf:Value> element, use of the <xccdf:complexchoice> element SHALL NOT be allowed. Use of complex values is disallowed because the behavior for mapping XCCDF complex values to OVAL variables is not defined. One or more <xccdf:check-export> elements MAY be used to define the binding of <xccdf:Value> elements to OVAL variables. The format of the <xccdf:check-export> element is: <xccdf:check-export value-id="XCCDF_Value_id" export-name="OVAL_External_Variable_id"/>

The following <xccdf:check> element example demonstrates the use of this convention:

<xccdf:check system="http://oval.mitre.org/XMLSchema/oval-definitions-5"> <xccdf:check-export value-id="xccdf_gov.nist.fdcc.xp_value_NoSlowLink" export-name="oval:gov.nist.fdcc.xp:var:66711"/> <xccdf:check-export valueid="xccdf_gov.nist.fdcc.xp_value_NoBackgroundPolicy" export-name="oval:gov.nist.fdcc.xp:var:66712"/>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

<xccdf:check-export valueid="xccdf_gov.nist.fdcc.xp_value_NoGPOListChanges" export-name="oval:gov.nist.fdcc.xp:var:66713"/> <xccdf:check-content-ref href="fdcc-winxp-oval.xml" name="oval:gov.nist.fdcc.xp:def:6671"/> </xccdf:check>

The type and value binding of the specified <xccdf:Value> is constrained to match the lexical representation of the indicated OVAL Variable data type. Table 18 summarizes the constraints regarding data type usage. Table 18. XCCDF-OVAL data export matching constraints OVAL Variable Data Type

Matching XCCDF Data Type

int float boolean string, evr_string, version, ios_version, fileset_revision, binary

number number boolean string

Additional information regarding OVAL data types can be found in the OVAL language documentation and the XCCDF specification [XCCDF]. Additional information on OVAL data types may also be added to Sec. 4 of the SCAP 1.4 annex document [SP800-126A]. 3.2.6. The <xccdf:Group> Element The XCCDF group extension SHALL NOT be allowed. 3.3. Open Vulnerability and Assessment Language (OVAL) This section lists requirements and recommendations for using the Open Vulnerability and Assessment Language (OVAL) to express an OVAL component of an SCAP source data stream (see Table 14). 9 Because SCAP 1.4 supports the use of multiple OVAL source data stream components, an SCAP content creator could choose to divide the OVAL definitions into multiple components. For example, a content creator could create one OVAL source data stream component that contains a set of OVAL definitions for one OVAL version (e.g., 5.10.1) and another set of OVAL definitions for a newer OVAL version (e.g., 5.12) if both versions are valid according to SCAP 1.4 requirements. SCAP 1.4 also supports multiple types of OVAL definitions within a single OVAL source data stream component. For example, a benchmark could reference OVAL compliance and vulnerability definitions contained in a single data stream component. The version of any particular OVAL document instance SHALL be specified using the <oval:schema_version> content element of the <oval:generator> element, as in this example:

9 See the SCAP 1.4 annex document [SP800-126A] for requirements regarding which OVAL versions shall or may be used in SCAP 1.4 content.

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Technical Specification for SCAP Version 1.4

<oval:generator> <oval:product_name>The OVAL Repository</oval:product_name> <oval:schema_version>5.12</oval:schema_version> </oval:generator>

The versions that are specified using the <oval:schema_version> content element SHALL correspond to the versions specified by the @xsi:schemaLocation attribute value for the OVAL schema if an @xsi:schemaLocation attribute is specified. Some OVAL interpreters make use of the OVAL variable format to allow variable values to be passed to the OVAL interpreter. While the OVAL variable format is not part of an SCAP data stream, this format can be used to carry variable information as part of an SCAP product for non-SCAP-related purposes. If an <oval-var:oval_variables> element is used to carry variable values between an XCCDF processor and an OVAL processor, the <oval:schema_version> of the <ovalvar:oval_variables> element SHALL be the same as that of the <ovaldef:oval_definitions> element whose external variables are bound by the <ovalvar:oval_variables> element. Required values for the @class attribute of an OVAL definition are as follows: 1. “Compliance” if it represents a check for the system’s configuration complying with policy requirements (e.g., having the required value for a specific configuration setting) 2. “Vulnerability” if it represents a check for the presence of a particular software flaw vulnerability on a system 3. “Patch” if it represents a check for whether a discrete patch needs to be installed on the system 4. “Inventory” if it represents a check for the presence of a product of interest on the system The following requirements apply to particular classes of OVAL definitions: 1. For compliance class definitions: a. If an OVAL compliance class definition maps to one or more CCE identifiers, the definition SHOULD include <oval-def:reference> elements that reference those identifiers using the following format: <oval-def:reference source="http://cce.mitre.org" ref_id="CCE_identifier"/>

The source attribute SHALL be defined using either “http://cce.mitre.org” (preferred method) or “CCE.” b. Definitions that are directly or indirectly extended SHALL be limited to inventory and compliance classes. 2. For inventory class definitions:

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

a. If an OVAL inventory class definition maps to one or more CPE identifiers, the definition SHOULD include <oval-def:reference> elements that reference those identifiers using the following format: <oval-def:reference source="http://cpe.mitre.org" ref_id="CPE_identifier"/>

The source attribute SHALL be defined using either “http://cpe.mitre.org” (preferred method) or “CPE.” b. Definitions that are directly or indirectly extended SHALL be limited to the inventory class. 3. For patch class definitions: a. If an OVAL patch class definition is associated with a source-specific identifier (e.g., Knowledge Base numbers for Microsoft patches), these identifiers SHOULD be included in <oval-def:reference> elements contained by the definition. For example: <oval-def:reference source="www.microsoft.com/Patch" ref_id="KB912919"/>

b. If an OVAL patch class definition maps to one or more CVE identifiers, the definition MAY include <oval-def:reference> elements that reference those identifiers using the following format: <oval-def:reference source="http://cve.mitre.org" ref_id="CVE_identifier"/>

This recommendation is weaker than its counterparts for the other class definition types because a CVE identifier is not an identifier for a patch; it is more of an association. For example, one patch could fix multiple vulnerabilities, so it would map to multiple CVE identifiers. The source attribute SHALL be defined using either “http://cve.mitre.org” (preferred method) or “CVE.” c. Definitions that are directly or indirectly extended SHALL be limited to inventory and patch classes. 4. For vulnerability class definitions: a. If an OVAL vulnerability class definition maps to one or more CVE identifiers, the definition SHOULD include <oval-def:reference> elements that reference those identifiers using the following format: <oval-def:reference source="http://cve.mitre.org" ref_id="CVE_identifier"/>

The source attribute SHALL be defined using either “http://cve.mitre.org” (preferred method) or “CVE.” b. Definitions that are directly or indirectly extended SHALL be limited to inventory and vulnerability classes. 29

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5. For miscellaneous class definitions, no additional requirements apply. 3.4. Open Checklist Interactive Language (OCIL) This section lists recommendations for using the Open Checklist Interactive Language (OCIL) to express an OCIL component of an SCAP source data stream (see Table 14). OCIL content SHOULD be used to check rules that cannot be fully automated with OVAL. For example, a particular software product may not have an application programming interface (API) that supports OVAL use. Another example is performing a check that requires user interaction, such as asking the user to look up information within a management console or to report a serial number affixed to a computing device. OCIL can also be used to collect a user’s own information, such as whether the user participated in a recent security training session. If an <ocil:questionnaire> element maps to one or more CCE, CVE, and/or CPE identifiers, it SHOULD include <ocil:reference> elements that reference those identifiers using the corresponding following format: <ocil:reference href="http://cce.mitre.org">CCE_identifier</ocil:reference> <ocil:reference href="http://cve.mitre.org">CVE_identifier</ocil:reference> <ocil:reference href="http://cpe.mitre.org">CPE_identifier</ocil:reference>

3.5. Common Platform Enumeration (CPE) This section lists requirements and recommendations for using Common Platform Enumeration (CPE) to express a CPE component of an SCAP source data stream (see Table 14). The Official CPE Dictionary data feed 10 MAY be used by SCAP components to reference CPE names. If use of the Official CPE Dictionary is impractical, a subset of the dictionary MAY be used instead. Creating the reduced official dictionary involves first identifying every CPE in <xccdf:platform> and <cpe2:fact-ref> elements contained within referenced <cpe2:platform-specification> elements in every benchmark in the data stream. These CPEs SHALL then be matched against every entry in the Official CPE Dictionary using the CPE name matching algorithm [CPE-M]. All CPEs matched in the official dictionary with a result of EQUAL or SUPERSET SHALL be included in the reduced official dictionary. One or more third-party dictionaries MAY be included in a data stream as well. All such thirdparty dictionaries SHOULD follow the requirements of the CPE Dictionary specification [CPE-D]. If including an entire third-party dictionary is impractical, a subset of the dictionary MAY be used instead. The reduced dictionary SHALL be created using the same procedure outlined for creating a subset of the official dictionary. In all cases, a dictionary component MAY be remote to the data stream collection.

10 The Official CPE Dictionary is available at https://nvd.nist.gov/products/cpe.

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Technical Specification for SCAP Version 1.4

Each CPE name [CPE-N] in an <xccdf:platform> or <cpe2:fact-ref> element within an XCCDF document SHALL match at least one CPE entry in a dictionary referenced by the data stream. A match is considered an EQUAL or SUPERSET result when matching the CPE name to a dictionary entry, as defined in the CPE Name Matching specification [CPE-M]. Only nondeprecated names SHOULD be used. Checklist authors SHOULD ensure that each CPE name [CPE-N] they specify in an <xccdf:platform> or <cpe2:fact-ref> element within an XCCDF document has a check associated with its CPE name. If a corresponding check does not exist, then it will not be possible to fully detect the presence of the product and determine platform applicability. [CPE-D] provides the defining structure of a CPE dictionary. A <cpe2_dict:cpe-item> element MAY contain one or more <cpe2-dict:check> elements that reference OVAL inventory class definitions. The referenced OVAL inventory class definition SHALL specify the technical procedure for determining whether or not a specific target asset is an instance of the CPE name specified by the <cpe2_dict:cpe-item> element. This usage is encouraged for CPE components. If a <cpe2_dict:cpe-item> element contained in a CPE component references an OVAL inventory class definition, then that definition SHALL be resolved by an @href attribute that references an OVAL source data stream component in the same data stream. Because there may be a lag between when a new product is available and when the Official CPE Dictionary is updated to include a CPE name for that product, third-party dictionaries may be needed to compensate. When creating a subset of the Official CPE Dictionary or a third-party dictionary, a <cpe2_dict:check> element on an entry MAY be added or modified if the existing check does not provide satisfactory content to test the presence of the CPE name. 3.6. Common Configuration Enumeration (CCE) To maintain consistency and accuracy, SCAP content that references a configuration setting SHALL use the official CCE identifier if a CCE entry for a particular configuration setting exists in the official CCE list. If no CCE entry exists for the configuration setting of interest, the content author SHOULD seek to have a CCE identifier issued for the configuration setting. See the OVAL compliance class definition requirements in Sec. 3.3 and the <xccdf:ident> requirements in Sec. 3.2.4.1 for additional requirements regarding CCE identifier references. The current official CCE list is available at https://ncp.nist.gov/cce, and new CCEs can be requested from NIST via email at cce@nist.gov. Use of an official, dynamic data feed is preferred over the static coding of CCE-related supporting information in SCAP data sources. For example, NVD provides a data feed 11 that is the authoritative mapping between CCE identifiers and the control identifiers defined in SP 80053. Embedding control identifiers within SCAP content is strongly discouraged due to the maintenance burden that it imposes on content maintainers when the control identifiers are revised. A preferred technique is to only embed CCE identifiers in SCAP content. When mappings to SP 800-53 control identifiers are needed, dynamically acquire them from the 11 See https://ncp.nist.gov/cce.

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Technical Specification for SCAP Version 1.4

official data feed, and associate them with the SCAP content based on its embedded CCE identifiers. 3.7. Common Vulnerabilities and Exposures (CVE) CVE references in SCAP content MAY use any CVE identifier in any non-deprecated state recognized by the CVE Program, including identifiers in the RESERVED state and identifiers in the PUBLISHED state. CVE identifiers in the REJECTED state, and any other deprecated CVE identifiers, SHALL NOT be used. If a CVE identifier exists for a particular vulnerability, the official CVE identifier SHALL be used. If no CVE exists for the software flaw, an alternate identifier MAY be used, but the content author SHOULD seek to have a CVE identifier issued for the vulnerability. Information on submitting unpublished vulnerabilities and obtaining CVE identifiers is available at https://cve.org. NIST provides public access to current CVE data - including descriptions, CVSS metrics, CPE applicability statements, and weakness (CWE) mappings - through two complementary mechanisms maintained by the National Vulnerability Database (NVD). Both mechanisms emit data conforming to the same JSON 2.0 schema, available at https://csrc.nist.gov/schema/nvd/api/2.0/cve_api_json_2.0.schema. •

Preferred mechanism - NVD CVE API 2.0. SCAP-conformant tools that consume CVE data dynamically SHOULD use the NVD CVE API 2.0. The API supports lookup by CVE identifier, time-bounded change retrieval (for incremental synchronization), and full enumeration with offset-based pagination. Documentation is available at https://nvd.nist.gov/developers/vulnerabilities, and a general developer on-ramp at https://nvd.nist.gov/developers. Production tools SHOULD register an NVD API key (see https://nvd.nist.gov/developers/request-an-api-key) so that per-source rate limits do not throttle synchronization during normal operation.

•

Supported alternative - NVD JSON 2.0 vulnerability feeds. Tools that perform bulk import or maintain a local mirror MAY consume the JSON 2.0 vulnerability feeds, available at https://nvd.nist.gov/vuln/data-feeds. The feeds are organized by CVEidentifier year (file naming ‘nvdcve-2.0-{YYYY}.json.gz’ and ‘.zip’), and additionally include "modified" and "recent" feeds covering changes within the previous eight days. Each feed is accompanied by a ‘.meta’ file (e.g., ‘nvdcve-2.0-{YYYY}.meta’) recording the last-modified timestamp, the uncompressed file size, and a SHA-256 hash of the uncompressed file. SCAP-conformant tools that synchronize via the JSON 2.0 feeds SHALL consult the corresponding ‘.meta’ file before downloading the feed payload, and SHALL NOT re-download a feed whose ‘.meta’ file is unchanged from the prior synchronization. NVD documents that this polling pattern, applied to all year and incremental feeds, results in fewer than 200 requests per day from a single consumer.

CVSS metric fields. The CVE record returned by both the API and the JSON 2.0 feeds carries CVSS metric data in version-specific fields. The field names are ‘cvssMetricV2’ (for CVSS v2.0; the absence of a minor-version digit in this field name is a known irregularity in the NVD schema relative to the v3.x and v4.0 fields), ‘cvssMetricV30’ (CVSS v3.0), ‘cvssMetricV31’ (CVSS 32

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Technical Specification for SCAP Version 1.4

v3.1), and ‘cvssMetricV40’ (CVSS v4.0). Sect. 3.8 specifies the SCAP 1.4 version-precedence rule under which SCAP-conformant tools select among these fields when more than one is populated for the same CVE. 3.8. Common Vulnerability Scoring System (CVSS) The NIST CVE data feed (see Sec. 3.7) is one source of CVSS base scores and vector data that MAY be used by SCAP-conformant products to support additional use cases built on SCAP, and MAY be used along with Threat, Temporal, Environmental, or Supplemental scores and vectors obtained from other authoritative sources. 3.8.1. Supported CVSS Versions SCAP 1.4 recognizes four CVSS versions, organized into two tiers: Current versions (for new SCAP content): -

CVSS v4.0 [CVSS-4.0] - preferred. SCAP-conformant content authored after the publication date of SP 800-126r4 SHOULD reference CVSS v4.0 vectors and scores when such data is available from an authoritative source.

CVSS v3.1 [CVSS-3.1] - supported. CVSS v3.1 vectors and scores SHALL be accepted by SCAP-conformant products when no CVSS v4.0 data is available for the referenced vulnerability.

Legacy versions (for pre-existing data only): -

CVSS v3.0 [CVSS-3.0] - legacy. CVSS v3.0 vectors and scores MAY be referenced solely for vulnerabilities published prior to 10 September 2019 (the date on which the NVD officially adopted CVSS v3.1 guidance for all new and re-analyzed CVEs) and only when neither a CVSS v3.1 nor a CVSS v4.0 vector has been issued for the same vulnerability.

CVSS v2.0 [CVSS-2.0] - legacy. CVSS v2.0 vectors and scores MAY be referenced solely for vulnerabilities published prior to 13 July 2022 (the date on which the NVD ceased generating new CVSS v2.0 vector strings) and only when no CVSS v3.0, v3.1, or v4.0 vector has been issued for the same vulnerability.

SCAP-conformant products SHALL identify the source CVSS version from the vector-string prefix where available - ‘CVSS:4.0/’, ‘CVSS:3.1/’, or ‘CVSS:3.0/’ - and SHALL NOT silently relabel a vector under a different version. Vectors lacking a ‘CVSS:’ prefix SHALL be treated as CVSS v2.0. 3.8.2. Version Precedence When more than one CVSS vector is available for the same vulnerability, SCAP-conformant products SHOULD select the version with the highest major number first, breaking ties on minor number. The resulting precedence is:  v4.0 > v3.1 > v3.0 > v2.0

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Technical Specification for SCAP Version 1.4

Products SHOULD record, alongside any CVSS score they emit, the CVSS version, the vector string, and the source (e.g., the NVD CVE feed entry identifier) so that downstream consumers can rederive or recompute the score against the authoritative source. 3.8.3. Metric Groups Products consuming CVSS v4.0 data SHOULD support the four metric groups defined by [CVSS4.0] - Base, Threat, Environmental, and Supplemental - and SHOULD preserve any nomenclature qualifier (CVSS-B, CVSS-BT, CVSS-BE, CVSS-BTE) reported by the source. Products consuming CVSS v3.1 or v3.0 data SHOULD support the three metric groups defined by [CVSS3.1] / [CVSS-3.0] - Base, Temporal, and Environmental. Products consuming CVSS v2.0 data SHOULD support the three metric groups defined by [CVSS-2.0] - Base, Temporal, and Environmental. 3.8.4. Known Limitation in XCCDF As noted in sect. 3.2.4.4, XCCDF does not provide a means to indicate which CVSS version was used when calculating an XCCDF score. SCAP-conformant tools that emit XCCDF results SHOULD therefore record the CVSS version and vector for each rule out-of-band (for example, in the corresponding ARF report or in tool-specific extensions) so that the version is recoverable by downstream consumers. This limitation is preserved from prior SCAP revisions and is not resolved by SCAP 1.4. 3.9. Common Configuration Scoring System (CCSS) CCSS base, temporal, and environmental scores and vectors MAY be used by products. Adopters should consider CCSS data in the context of organizational security policies and dependencies among vulnerabilities. See [CCSS] for additional information. 3.10. XML Digital Signature Digitally signing source data streams helps ensure the integrity and trustworthiness of legitimate content by preventing unauthorized content from being processed. Leveraging the TMSAD specification [TMSAD] for SCAP improves the legitimacy of authoritative content. Content authors SHOULD digitally sign SCAP source data stream collections in accordance with [TMSAD] and the requirements provided in this section. 3.10.1. Signature Location If a digital signature is included in a source data stream collection, it SHALL be placed as the last element within the source data stream collection root element.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

3.10.2. Signature Representation Each digital signature SHALL be represented as a <ds:Signature> element and SHALL conform to the W3C XML Signature Syntax and Processing recommendation [DSIG]. The “ds” prefix is used in this section for clarity; any equivalent prefix bound to the XMLDSIG namespace MAY be used. 3.10.3. Signature Requirements The <ds:Signature> element SHALL follow the recommendations in [TMSAD] and the following additional requirements: a) Each <ds:Signature> SHALL cover exactly one target: 1) The source data stream collection root element or 2) A single data stream. b) If the <ds:Signature> element targets the source data stream collection root element, the <ds:SignedInfo> element contained within SHALL contain exactly one <ds:Reference>. The <ds:Reference> SHALL have a target URI of one of the following: 1) If the URI is an empty string otherwise represented as “”, the URI target SHALL be considered to refer to the source data stream collection root element. 2) If the URI is a defined ID, then it SHALL be a same-document reference (e.g., #id) that resolves to the source data stream collection root element. c) If the <ds:Signature> element targets a single data stream, then the <ds:SignedInfo> element SHALL contain a same-document reference (e.g., #id) that resolves to the data stream collection being signed along with either: 1) A set of same-document references (e.g., #id) that resolve to each local component referenced by the data stream being signed or 2) A same-document reference (e.g., #id) that resolves to a <ds:Manifest> element contained within the <ds:Signature> as a <ds:Object> element. The referenced <ds:Manifest> element SHALL have a <ds:Reference> element for each local component referenced by the data stream being signed. External components MAY be omitted from the <ds:Manifest> element. Each <ds:Reference> element referencing a <ds:component> or <ds:extended-component> SHALL point to the component being signed by identifying the component in the @URI attribute using “#” and the @Id of the component.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

3.10.4. Key Information Cryptographic key information SHOULD be provided in the <ds:Signature> element through use of the <ds:KeyInfo> sub-element. For example: <scap-ds:source-data-stream-collection xml:id="sds-1" ...>  <ds:Signature Id="sig-sds-1"> <ds:SignedInfo> <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xmlexc-c14n#"/> <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsigmore#rsa-sha256"/> <ds:Reference URI=""> <ds:Transforms> <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/> </ds:Transforms> <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/> <ds:DigestValue>...</ds:DigestValue> </ds:Reference> </ds:SignedInfo> <ds:SignatureValue>...</ds:SignatureValue> <ds:KeyInfo> <ds:X509Data> <ds:X509Certificate>...</ds:X509Certificate> </ds:X509Data> </ds:KeyInfo> </ds:Signature> </scap-ds:source-data-stream-collection>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4. SCAP Content Processing Requirements and Recommendations This section defines the processing requirements that SCAP content consumers SHOULD follow to correctly process SCAP 1.4 content. This section also provides recommendations that content producers and consumers are encouraged to adopt to promote stronger interoperability and greater consistency. 4.1. Legacy Support Content consumers that support SCAP 1.4 may be interested in supporting earlier version of SCAP (i.e., SCAP 1.3) if there is little difference between the two content streams. 12 Content consumers that process legacy SCAP content SHOULD be capable of outputting results in the current SCAP revision. Additionally, content consumers MAY output results in the same SCAP version as the source content. For producers of results in legacy formats, legacy results MAY also be converted into results based on the current SCAP revision. Certain constructs can be deprecated in the SCAP component specifications. 13 SCAP content consumers SHOULD support deprecated constructs unless specifically noted in the annex because they are still valid in SCAP 1.4 and supported legacy SCAP versions. This recommendation ensures that legacy SCAP content that uses these deprecated constructs will continue to be supported. Content consumers that support OVAL SHOULD support OVAL definition documents written against all versions of OVAL component specifications listed in the annex. 4.2. Source Data Streams Content consumers SHALL be capable of validating SCAP content against the appropriate schemas and Schematron stylesheets, detecting and reporting errors, and failing gracefully if there are errors. The relevant XML schemas and Schematron rule sets are available at https://csrc.nist.gov/Projects/security-content-automation-protocol/scap-releases/scap-1-4. See Sec. 3.1 for additional information on the Schematron rule sets. Content consumers SHOULD validate XML digital signatures if they exist in the content. Validating a signature includes confirming that the signature value is valid, all of the reference hashes in the signature and manifest are correct, and the public key used to verify the signature is from a trusted source. A data stream with a signature that does not validate SHOULD NOT be evaluated by a content consumer. When a <ds:extended-component> that is not recognized by the tool is referenced from a <ds:data-stream>, <ds:component>, or <ds:extended-component> element, the tool SHALL issue a warning. If more than one <ds:data-stream> element is specified on the <ds:data-streamcollection>, the ID of the <ds:data-stream> to execute SHALL be indicated to the 12 See https://csrc.nist.gov/pubs/sp/800/126/r2/final (SCAP 1.2) and https://csrc.nist.gov/pubs/sp/800/126/r3/final (SCAP 1.3).

13 The OVAL Language Deprecation policy is available at https://oval-community-guidelines.readthedocs.io/en/base/deprecation.html.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

content consumer, and the content consumer SHALL use the specified <ds:data-stream>. If more than one <xccdf:Benchmark> is referenced by a <ds:data-stream>, the ID of the <xccdf:Benchmark> to execute SHALL be indicated to the content consumer, and the content consumer SHALL process the indicated <xccdf:Benchmark>. Because SCAP and its component specifications do not formally define how to designate a particular data stream or benchmark, it is expected that products will implement these capabilities in a proprietary way. 4.3. XCCDF Processing The following requirements and recommendations pertain to content consumers processing XCCDF benchmark and tailoring components from an SCAP source data stream. 4.3.1. CPE Applicability Processing CPEs referenced in an <xccdf:platform> element directly or by a <cpe2:fact-ref> contained within a referenced <cpe2:platform-specification> element SHALL be evaluated as follows to determine their presence on a machine: 1. The CPE SHALL be matched against all CPEs in all of the dictionaries referenced by the <ds:data-stream> element. All CPEs that return an EQUAL or SUPERSET result as defined in CPE Name Matching [CPE-M] SHALL be used in evaluating the <xccdf:platform> or <cpe2:fact-ref>. 2. Either a list of CPEs found on the target asset SHALL be known before the scan, or a list SHALL be generated. If a previously known list is used, it SHALL be equivalent to a newly generated list. To generate the list, the <cpe2_dict:check> element data associated with the found <cpe2_dict:cpe-item> elements SHALL be evaluated against the target using the referenced OVAL inventory class definition. If a <cpe2_dict:check> returns “pass,” then the corresponding CPE SHALL be added to the list of CPEs found on the target. 3. The list of CPEs found on the target asset and either the <xccdf:platform> or the <cpe2:platform-specification> SHALL be used as input to the CPE Applicability Language [CPE-L] algorithm to determine the XCCDF benchmark applicability to the target asset. 4.3.2. Checking System Usage If an XCCDF component has multiple <xccdf:check-content-ref> elements, then check processing SHOULD be performed according to [XCCDF:7.2.3.5.1] with the following changes: 1. For each <xccdf:check-content-ref> element, a content consumer either SHALL attempt to retrieve the document referenced by the <ds:component-ref> element that is referenced directly by the <xccdf:check-content-ref> element’s @href attribute, or it SHALL resolve the @href attribute within the context of the XML Catalog specified as part of the <ds:component-ref> element used to reference this

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

benchmark. If not resolvable, the next available <xccdf:check-content-ref> element SHALL be evaluated. If none of the <xccdf:check-content-ref> elements are resolvable, then the result of the rule evaluation SHALL be the XCCDF “notchecked” status, and processing of the check SHALL end. 2. Once a resolvable <xccdf:check-content-ref> element is found, then checking system processing SHALL proceed. When evaluating a rule, an <xccdf:ruleresult/xccdf:message> with the @severity attribute value of “info” SHALL be generated, indicating the <xccdf:check-content-ref> @href attribute and @name attribute, if provided. Content consumers SHOULD implement checking systems that are supported by SCAP, as defined in Sec. 3.2.4.2. Content consumers MAY implement checking systems that are not supported by SCAP. If a tool encounters a checking system it does not support, it SHOULD issue a warning, and it SHOULD continue processing according to the [XCCDF] specification. 4.4. SCAP Result Data Streams An SCAP result data stream contains the results of the evaluation of one or more SCAP source data streams by an SCAP content consumer. The following requirements and recommendations pertain to content consumers that generate SCAP result data streams. An SCAP result data stream SHALL conform to the [ARF] specification. The following sections outline the details of the ARF report. In all situations, one or more component results (e.g., XCCDF, check results), the target asset, and/or the SCAP source data stream collection represented as a report request in ARF MAY be represented either as a local component in the ARF or as a remote resource, leveraging the remote resource capability built into ARF. The following is a stripped down ARF example: <arf:asset-report-collection> <rc:relationships> <rc:relationship type="arf-rel:isAbout" subject="xccdf1"> <rc:ref>asset1</rc:ref> </rc:relationship> <rc:relationship type="arf-rel:isAbout" subject="oval1"> <rc:ref>asset1</rc:ref> </rc:relationship> <rc:relationship type="scap-rel:checkContext" subject="oval1"> <rc:ref>xccdf1</rc:ref> </rc:relationship> <rc:relationship type="scap-rel:fromSource" subject="xccdf1"> <rc:ref>collection1</rc:ref> </rc:relationship> <rc:relationship type="scap-rel:fromSource" subject="oval1"> <rc:ref>collection1</rc:ref> </rc:relationship> </rc:relationships> <arf:report-requests> <arf:report-request id="collection1"> <arf:content> <ds:data-stream-collection>…</ds:data-stream-collection>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

</arf:content> </arf:report-request> </arf:report-requests> <arf:assets> <arf:asset id="asset1"> <ai:computing-device>…</ai:computing-device> </arf:asset> </arf:assets> <arf:reports> <arf:report id="xccdf1"> <arf:content> <xccdf:TestResult>…</xccdf:TestResult> </arf:content> </arf:report> <arf:report id="oval1"> <arf:content> <oval-res:oval_results>…</oval-res:oval_results> </arf:content> </arf:report> </arf:reports> </arf:asset-report-collection>

4.4.1. The Component Reports The ARF report SHALL contain a report object for each XCCDF, OVAL, and OCIL component executed when a source data stream is evaluated against a target. It MAY contain additional report objects for other results, such as <oval-var:oval_variables> or extended component results. Each component result SHALL be captured as a separate <arf:report> element in the <arf:asset-report-collection> element.14 When reporting on XCCDF, OVAL, or OCIL, each component report SHALL use the element specified in Table 19 as its root element. Table 19. SCAP result data stream component document elements Component XCCDF OVAL OCIL

Document Element <xccdf:TestResult>

<oval-res:oval_results> <ocil:ocil>

SCAP result data stream components SHOULD NOT use any deprecated constructs in their associated specifications. Validation of each component SHALL be done in accordance with the portions of this document that define requirements for the component. See Sec. 3.1.2 for more information on the SCAP Content Validation Tool, which can help validate the correctness of SCAP result data streams.

14 For example, if two check components were executed, one referenced by a <ds:component-ref> element of a <ds:dictionaries> element and another one referenced by a <ds:component-ref> element of a <ds:checklists> element, the ARF report will include two separate <arf:report> elements, one for each executed component.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4.4.2. The Target Identification The target asset SHALL be represented in the ARF report using the <ai:assets> part of ARF. The <ai:asset> element populated about a target asset SHOULD include the fields specified in Table 20, where applicable. Table 20. Asset identification fields to populate Field

Ethernet media access control address Internet Protocol version 4 address Internet Protocol version 6 address Host name Fully qualified domain name

Location Within Asset Identification Computing Device

connections/connection/mac-address connections/connection/ip-address/ip-v4 connections/connection/ip-address/ip-v6 hostname fqdn

Additional identification information MAY be captured in the <ai:asset> element (e.g., asset tag, system GUID). The guidelines specified in [AI] SHALL be followed when populating the asset identification information. Currently, only the target asset of the SCAP evaluation is identified. 4.4.3. The Source Data Stream The source data stream collection that was used to generate the results against the target SHOULD be included in the ARF report as an <arf:report-request>. If the source data stream collection is included in the ARF report, and an <xccdf:Tailoring> component was used during processing, the tailoring component SHALL be included as well. The following is a stripped-down example: <arf:asset-report-collection> <arf:report-requests> <arf:report-request id="request_0"> <arf:content> <ds:data-stream-collection id="..."  ... </ds:data-stream-collection> </arf:content> </arf:report-request> <arf:report-request id="request_1"> <arf:content> <ds:data-stream-collection id="..."  ... </ds:data-stream-collection> </arf:content> </arf:report-request> </arf:report-requests> <arf:assets>...</arf:assets> <arf:reports>...</arf:reports> </arf:asset-report-collection>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4.4.4. The Relationships Table 21 outlines the relationships that SHALL be specified in the ARF report if the stated condition is satisfied. Table 21. ARF relationships Relationship

Condition

Cardinality

Definition

Subject

Object

Each report is reporting about the asset Each check report is reporting in the context of the benchmark report Each component report was generated from the SCAP source content Each OVAL variables report is associated with an OVAL result

Component report

Target asset

Check component report

Benchmark component report

Component report

Report request

Component report of OVAL variables

Component report of OVAL results

arf-rel:isAbout

None

One for each component report

scap-rel:checkContext

Benchmark report exists

One for each check component report (OVAL or OCIL)

scap-rel:fromSource

Report request exists

One for each component report

scap-rel:associatedWith

OVAL variables report is provided

One for each OVAL variables component report

Figure 3 gives an example of how the resulting ARF report would look. arf-report

target-asset

scap-datastream

xccdf-result1

Legend arf-rel:isAbout

oval-result1

scap-rel:fromSource

oval-result2

asset

ocil-result1

scap-rel:checkContent

report report-request

Fig. 3. Sample ARF report structure

4.5. XCCDF Results The following requirements and recommendations pertain to content consumers that generate XCCDF result data stream components. Each XCCDF result data stream component SHALL comply with the XCCDF Results schema.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

XCCDF test results SHALL be documented as the contents of an <xccdf:TestResult> element. To be considered valid SCAP result content, the <xccdf:TestResult> element SHALL meet the following conditions: 1. The @start-time and @end-time attributes SHALL be provided to indicate when the scan started and completed, respectively. 2. The @test-system attribute SHALL be provided, and it SHALL be a CPE name value indicating the product that was responsible for generating the results. 3. When the <xccdf:TestResult> is the root XCCDF element, then it will include an <xccdf:benchmark> element [XCCDF:6.6.2]. a. The <xccdf:benchmark> element SHALL have an @id attribute specified. The @id attribute SHALL match the value of the <xccdf:Benchmark> element’s @id attribute that was processed. b. The <xccdf:benchmark> element SHALL have an @href attribute specified. The @href attribute SHALL hold the URI that references the XCCDF component (i.e., either local to the data stream collection or remote) that was processed. The URI SHALL be in the form specified for the @href attribute in Table 8. 4. If a child profile of an <xccdf:Tailoring> element was applied during processing, then the <xccdf:tailoring-file> element SHALL be present and SHALL provide the following information about the <xccdf:Tailoring> element: @href, @id, @version, and @time. The @href attribute SHALL hold the URI to the XCCDF tailoring component and SHALL comply with the format described above (item 3). 5. The <xccdf:Profile> element SHALL be included if a profile was applied during processing. This is also applicable to selected profiles that are part of <xccdf:Tailoring>. 6. Regarding the definition and use of <xccdf:Profile> elements, reported <xccdf:set-value> elements SHALL include all those values that are exported by the reported rules. The specific settings are those determined by the reported <xccdf:Profile>. 7. The <xccdf:identity> element SHALL identify the security principal used to access rule evaluations on the targets. This will include the identity name or username used to perform the evaluation. 8. Each IP address associated with the <xccdf:target> SHALL be enumerated using the <xccdf:target-address> element. 9. An <xccdf:target-id-ref> SHALL be specified with a @system attribute of “http://scap.nist.gov/schema/asset-identification/1.1”, an @href attribute value of “”, and a @name attribute value of the ID of the <ai:asset> element in the ARF that this <xccdf:TestResult> is about. 10. The <xccdf:rule-result> elements report the result of the application of each selected rule [XCCDF:6.6.2]. The @role, @severity, and @weight attributes of the 43

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

<xccdf:rule-result> element SHALL be provided to indicate the values used during assessment. The <xccdf:check/xccdf:check-content-ref> element SHALL

record the reference to the checking system-specific result component report ID and check name within the result file using the @href and @name attributes, respectively. The @href attribute SHALL contain “#” and the @id of the <arf:report> that contains the check result. This approach provides traceability between XCCDF and check results. If @multi-check is not set to “true,” and the <xccdf:rule-result> represents a group of checks, then the @name attribute SHALL be omitted. See the example below the next requirement. 11. Where applicable to the target system, each of the <xccdf:fact> elements in Table 22 SHALL be provided. Previous versions of SCAP required additional facts; these have been incorporated into the use of the Asset Identification specification, as discussed in Sec. 4.4.2. Table 22. XCCDF fact descriptions XCCDF Fact

Description of Use

urn:scap:fact:asset:identifier:ein

Equipment identification number or other inventory tag number

urn:scap:fact:asset:identifier:guid

Globally unique identifier for the asset, if assigned

urn:scap:fact:asset:environmental_information: owning_organization

Organization that tracks the asset on its inventory

urn:scap:fact:asset:environmental_information: current_region

Geographic region where the asset is located

urn:scap:fact:asset:environmental_information: administration_unit

Name of the organization that does system administration for the asset

The following is a stripped-down example that illustrates the above requirements: <arf:asset-report-collection> <rc:relationships>...</rc:relationships> <arf:report-requests>...</arf:report-requests> <arf:assets>...</arf:assets> <arf:reports> <arf:report id="scap_gov.nist_comp_r3005-xccdf_01"> <arf:content> <xccdf:TestResult start-time="2016-03-10T10:07:11" version="1-2.1.0.0" test-system="cpe:/a:vendor:product_name:version" end-time="2016-03-10T10:07:11" id="xccdf_gov.nist_testresult_..."> <xccdf:benchmark href="file:r3005-ds-01.xml#scap_gov.nist_comp_r3005-xccdf_01" id="xccdf_gov.nist_benchmark_r3005_id_01"/> <xccdf:tailoring-file

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4 href="#scap_gov.nist_comp_r3005-xccdf_tailoring_03" id="xccdf_gov.nist_tailoring_r3005_03" time="2016-01-22T14:00:00" version="1-2.1.0.0"/>

<xccdf:organization>...</xccdf:organization> <xccdf:identity privileged="true" authenticated="true"> ... </xccdf:identity> <xccdf:profile idref="xccdf_gov.nist.val_profile_r3005_tailoring_03"/> <xccdf:target>...</xccdf:target> <xccdf:target-address>...</xccdf:target-address> <xccdf:target-facts>...</xccdf:target-facts> <xccdf:target-id-ref system="http://scap.nist.gov/schema/asset-identification/1.1" href="" name="..." /> <xccdf:set-value idref="xccdf_gov.nist_value_val.r3005_for_rule_6">test0</> ... <xccdf:rule-result time="2016-03-10T10:07:11" idref="xccdf_gov.nist_rule_val.r3005_rule_1" weight="10" severity="medium" role="full"> <xccdf:result>pass</xccdf:result> <xccdf:check system="http://oval.mitre.org/XMLSchema/oval-definitions-5" selector="sel1"> <xccdf:check-content-ref href="#scap_gov.nist_comp_r3005-oval" name="oval:nist.validation.r3005:def:2"/> </xccdf:check> </xccdf:rule-result> </xccdf:TestResult> </arf:content> </arf:report> <arf:report id="scap_gov.nist_comp_r3005-oval"> <arf:content> <arf:oval-res:oval_results>...</oval-res:oval_results> </arf:content> </arf:report> </arf:reports> </arf:asset-report-collection>

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4.5.1. Assigning Identifiers to Rule Results The <xccdf:rule-result> element provides data that indicates the result of assessing a system using the identified <xccdf:Rule> element. If the target <xccdf:Rule> identified by the <xccdf:rule-result> element’s @idref attribute has one or more <xccdf:ident> elements with a @system attribute value listed in Sec. 3.2.4.1, then each <xccdf:ident> element SHALL also appear within the <xccdf:rule-result> element. If the <xccdf:ident> element is included, it is important for tracking purposes that produced XCCDF results have specific meanings. If an <xccdf:ident> element is present, and it identifies a CVE, CCE, or CPE entry, then an <xccdf:rule-result> of “pass” SHALL indicate that the check content evaluated within the rule complied with one of the following: •

For a CVE entry, the target platform satisfies all of the conditions of the XCCDF rule and is unaffected by the vulnerability or exposure referenced by the CVE.

•

For a CCE entry, the target platform complies with the configuration-setting guidance expressed in the XCCDF rule.

•

For a CPE entry, the target platform was identified on the system.

These interpretations of <xccdf:ident> elements must be preserved. For example, consider two policy recommendations. One is that a particular piece of software be installed, and the second is that another piece of software should not be installed. Both rules for these policy recommendations could use the same CPE entry in their <xccdf:ident> elements. However, because the interpretation of a CPE entry is that a “pass” result indicates that software was installed, the second policy recommendation’s rule would violate this. This can be corrected by using the @con:negate attribute, which is a Boolean attribute that inverts the rule result. The second rule could check for the software being installed and then negate that result, thus giving a result that is consistent in meaning with the first rule. For rules that cannot have their interpretations preserved through the use of the @con:negate attribute, an alternative is to have a CCE entry correspond to the recommendation. Rules that do not use <xccdf:ident> elements have no such restrictions. 4.5.2. Mapping OVAL Results to XCCDF Results When evaluating an <xccdf:Rule> element that references an OVAL definition, the <xccdf:rule-result> element SHALL be used to capture the result of this evaluation. This result SHALL be determined by evaluating the referenced OVAL definition on a target host. The resulting value of an individual <xccdf:check> SHALL be mapped from the OVAL definition result produced during evaluation. The corresponding <xccdf:ruleresult/xccdf:result> value is then computed based on the result values of all relevant <xccdf:check> elements. 15 While the OVAL specification permits limiting result status

15 Normally, only a single <xccdf:check> element is needed. However, if an <xccdf:complex-check> element is used, there may be

multiple results that must be combined, as outlined in the XCCDF specification.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

reporting, SCAP-conformant content SHALL provide full status reporting, including error, unknown, not applicable, not evaluated, true, and false. Content consumers SHALL apply the mapping illustrated in Table 23 when deriving <xccdf:check> results from OVAL definition processing. Table 23. Deriving XCCDF check results from OVAL definition results OVAL Definition Result

XCCDF Check Result (@negate is set to “false”) error unknown notapplicable notchecked

XCCDF Check Result (@negate is set to “true”) error unknown notapplicable notchecked

error unknown not applicable not evaluated Definition Class compliance vulnerability inventory patch

Definition Result true false true false

pass

fail

Definition Class compliance vulnerability inventory patch

Definition Result False true false true

fail

pass

The corresponding result value SHALL be recorded based on the @class attribute of the OVAL definition and the @negate attribute of the <xccdf:check> element, where applicable. The mappings in Table 23 are specific to each OVAL definition class. For example, if an OVAL compliance class definition is processed, and OVAL returns a result of “true,” the content consumer is conveying the fact that the system was found to be compliant with that check and therefore returns a “pass” result for that check. A similar definition for a vulnerable condition will return results of “false” if that vulnerability was not found on the examined devices, resulting in a “pass” from the XCCDF check. Negations of check results or their combination in complex checks may result in additional modification before the final corresponding <xccdf:rule-result/xccdf:result> value is known. If the <xccdf:Rule> element under evaluation has an <xccdf:check-content-ref> element with the @name attribute omitted and an <xccdf:check> element with its @multicheck attribute set to “true,” then the result of each evaluated OVAL definition SHALL be recorded as a separate <xccdf:rule-result> element. In this case, the <xccdf:ruleresult>/<xccdf:check-content-ref> element SHALL identify the specific check result of each evaluated OVAL definition using the @href and @name attributes, as described in Sec. 4.5, item 8. According to [XCCDF:Table 9;Table 35;Table 39], if the <xccdf:Rule> element under evaluation is selected, and its @role attribute is set to ”unchecked,” then the rule result SHALL be set to “notchecked.” If the <xccdf:Rule> element under evaluation is selected, and its @role attribute is set to “unscored,” then the rule result SHALL be set to “informational.” 47

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4.6. OVAL Results The following requirements and recommendations pertain to content consumers that generate OVAL result data stream components. See the annex for additional requirements and recommendations. Each OVAL result data stream component SHALL validate against at least one version of the OVAL results schema that corresponds to an OVAL component specification version that was specified in Sect. 2 of the annex, regardless of the version of the OVAL definitions document that was evaluated. An SCAP OVAL result data stream component SHALL include the results of every OVAL definition used to generate the reported results. In order to be SCAP-conformant, an SCAP content consumer SHALL be able to produce all types of OVAL result outputs described below. The specific result output SHALL be configurable within the SCAP content consumer. In order to support SCAP instances where OVAL thin content (i.e., only the ID of the definition and the results) is preferred, SCAP content consumers SHALL support all valid values for the <oval-res:directives> that control the expected content of the results file. To support the ability for results to be consumed by appropriate products, data results SHALL be expressed as a single machine without system characteristics, single machine with system characteristics, or single machine with thin results as follows: 1. Single machine without system characteristics — A single result file that includes the results of all OVAL definitions evaluated and “full” result types, as described in the <oval-res:ContentEnumeration> element, without system characteristics. For this format, the values for the <oval-res:directives> element SHALL be: <oval-res:directives include_source_definitions="false"> <oval-res:definition_true content="full" reported="true"/> <oval-res:definition_false content="full" reported="true"/> <oval-res:definition_unknown content="full" reported="true"/> <oval-res:definition_error content="full" reported="true"/> <oval-res:definition_not_evaluated content="full" reported="true"/> <oval-res:definition_not_applicable content="full" reported="true"/> </oval-res:directives>

When creating the OVAL system characteristics, as defined by the <ovalsc:oval_system_characteristics> element, the <ovalsc:collected_objects> and <oval-sc:system_data> elements SHALL NOT be provided. 2. Single machine with system characteristics — A single result file that includes the results of all OVAL definitions evaluated and “full” result types, as described in the <ovalres:ContentEnumeration> element and the system characteristics of the target evaluated. For this format, the values for the <oval-res:directives> element SHALL be:

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

<oval-res:directives include_source_definitions="false"> <oval-res:definition_true content="full" reported="true"/> <oval-res:definition_false content="full" reported="true"/> <oval-res:definition_unknown content="full" reported="true"/> <oval-res:definition_error content="full" reported="true"/> <oval-res:definition_not_evaluated content="full" reported="true"/> <oval-res:definition_not_applicable content="full" reported="true"/> </oval-res:directives>

When creating the OVAL system characteristics, as defined by the <ovalsc:oval_system_characteristics> element, the <oval-sc:collected_objects> and <oval-sc:system_data> elements SHALL be provided. 3. Single machine with thin results — A single result file that includes the results of all OVAL definitions evaluated and “thin” result types, as described in the OVAL results schema. A value of “thin” means that the minimal amount of information will be provided. For this format, the values for the <oval-res:directives> element SHALL be: <oval-res:directives include_source_definitions="false"> <oval-res:definition_true content="thin" reported="true"/> <oval-res:definition_false content="thin" reported="true"/> <oval-res:definition_unknown content="thin" reported="true"/> <oval-res:definition_error content="thin" reported="true"/> <oval-res:definition_not_evaluated content="thin" reported="true"/> <oval-res:definition_not_applicable content="thin" reported="true"/> </oval-res:directives>

When specifying OVAL system characteristics, a reference SHOULD be made to the target asset in the ARF report collection. Specifically, the <ovalsc:oval_system_characteristics>/<oval-sc:system_info> SHOULD be populated with a <con:asset-identification> element. That element SHALL be populated with a single <arf:object-ref> element that points to the <ai:asset> element in the ARF report collection pertaining to the OVAL result. See [ARF] for details on populating the <arf:objectref> element. 4.7. OCIL Results The following requirements and recommendations pertain to content consumers that generate OCIL result data stream components. An SCAP OCIL result data stream component SHALL include the results of every <ocil:questionnaire>, <ocil:question_test_action>, and <ocil:question> element used to generate the reported results. 4.8. Result Data Stream Signing Digitally signing SCAP result content is important for establishing integrity and provenance and for enabling content consumers to make trust decisions in accordance with [TMSAD]. Content

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

consumers SHOULD digitally sign SCAP result content in accordance with [TMSAD] and the requirements in this section. 4.8.1. Signature Location If a digital signature is included within a source data stream collection, it SHALL be placed in an <arf:extended-info> element within the ARF report. 4.8.2. Signature Representation Each digital signature SHALL be represented as a <ds:Signature> element and SHALL conform to the W3C XML Signature Syntax and Processing recommendation [DSIG]. The “ds” prefix is used in this section for clarity; any equivalent prefix bound to the XMLDSIG namespace MAY be used. 4.8.3. Signature Requirements The <ds:Signature> element SHALL follow the recommendations in [TMSAD] along with the following additional requirements. a) The <ds:Signature> SHALL cover exactly one target: the <arf:asset-reportcollection> element (i.e., the ARF report). b) The first <ds:Reference> element in a <ds:Signature> element SHALL be to the <arf:asset-report-collection> element. The element SHALL be referenced in the @URI attribute using the empty string convention “”. c) Two XPath Filter 2 transforms SHALL exist on the first <dsig:Reference> element in a <dsig:Signature> element. Both SHALL specify a filter type of “subtract.” The first transform SHALL specify the XPath /arf:asset-reportcollection/arf:extended-infos[count(arf:extendedinfo[dsig:Signature]) = count(*)]. The second transform SHALL specify the XPath /arf:asset-report-collection/arf:extendedinfos/arf:extended-info[dsig:Signature]. In both cases, the namespace

prefix “arf” SHALL map to the ARF namespace specified in this document.

d) The second <dsig:Reference> element MAY be to the <dsig:SignatureProperties> element captured in a <dsig:Object> element with the <dsig:Signature> element. The <dsig:SignatureProperties> element SHALL be referenced in the @URI attribute using “#” and the @Id of the <dsig:SignatureProperties> element. 4.8.4. Key information Key information SHOULD be provided on the <dsig:Signature> element.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

4.8.5. Countersigning If countersigning the result is desired (e.g., a system signs automatically, and a human reviewer later adds a signature), the following SHALL apply: a) The <arf:extended-info> element that contains the original signature SHALL be removed from the resulting document. b) The original signature SHALL be captured as a <dsig:Object> element on the new <dsig:Signature> element. c) The first <dsig:Reference> element in the new <dsig:Signature> element SHALL reference the <dsig:Object> element that contains the original signature. The <dsig:Object> element SHALL be referenced in the @URI attribute using “#” and the @Id of the <dsig:Object> element. d) If the <dsig:SignatureProperties> element existed within the original signature, the second <dsig:Reference> element SHALL be to the <dsig:SignatureProperties> element captured in a <dsig:Object> element with the <dsig:Signature> element. The <dsig:SignatureProperties> element SHALL be referenced in the @URI attribute using “#” and the @Id of the <dsig:SignatureProperties> element. e) A <dsig:SignatureProperties> element MAY be included in the <dsig:Signature> element. At least one <dsig:SignatureProperty> element MAY be populated with <dt:signature-info>, as specified in [TMSAD]. f) Key information SHOULD be provided on the <dsig:Signature> element in accordance with [TMSAD]. g) The new <dsig:Signature> element SHALL be placed in a new <arf:extendedinfo> element in the ARF report collection. A signature that has countersigned another signature (also known as an enveloping signature) MAY be countersigned. When doing so, the requirements above SHALL apply to the new signature creation.

NIST SP 800-126r4 June 2026

Technical Specification for SCAP Version 1.4

5. Source Data Stream Content Requirements for Use Cases This section discusses additional requirements for the following SCAP-conformant content use cases: compliance checking, vulnerability scanning, and inventory scanning. As stated in Table 3, each data stream is required to have a @use-case attribute in its <ds:data-stream> element with a value that corresponds to either one of the content types defined in this section or to “OTHER” for data streams that do not correspond to a defined use case. The required value for each content type is specified in the following subsection. Each use case is subject to the requirements presented in this section as well as all applicable requirements in Sec. 3 and 4. 5.1. Compliance Checking SCAP content can be used to compare system characteristics and settings against an SCAPconformant checklist in an automated fashion. This can verify that operating systems and applications comply with security checklists and identify any deviations from those checklists. The SCAP source data stream component that SHALL be included for compliance checking is the XCCDF benchmark, which expresses the checklist. Each rule in the XCCDF benchmark SHALL reference one of the following: •

An OVAL compliance definition. This definition SHALL be contained in an OVAL component, which holds definitions of compliance checks used by the checklist. An XCCDF benchmark’s rules MAY reference one or more OVAL compliance class definitions in an OVAL component.

•

An OCIL questionnaire. This questionnaire SHALL be contained in an OCIL component, which holds questionnaires that collect information that OVAL is not being used to collect, such as posing questions to users or harvesting configuration information from an existing database. An XCCDF benchmark’s rules MAY reference one or more OCIL questionnaires in an OCIL component.

•

An OVAL patch definition. This definition SHALL be contained in an OVAL component, which holds definitions for patch compliance checks. These checks may be needed if an organization includes patch verification in its compliance activities. An XCCDF benchmark MAY reference an OVAL patch definition through a patches up-to-date rule in a manner consistent with Sec. 3.2.4.3.

Each XCCDF benchmark SHALL have at least one rule that references either an OVAL compliance class definition in an OVAL component or an OCIL questionnaire in an OCIL component. All OVAL components and OCIL components referenced by the XCCDF benchmark SHALL be included in the SCAP source data stream. If the XCCDF benchmark component references any CPE names, then the SCAP source data stream SHALL include a CPE component, which specifies the products or platforms of interest, and SHALL include one or more OVAL inventory class definitions in an OVAL component that 52

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Technical Specification for SCAP Version 1.4

contain the technical procedures for determining whether or not a specific target asset has a product or platform of interest. The @use-case attribute in the <ds:data-stream> element SHALL be set to “CONFIGURATION.” 5.2. Vulnerability Scanning SCAP content can be used to scan operating systems and applications to look for known software flaws that introduce security exposures. The content enables the consistent detection and reporting of these flaws. The SCAP source data stream component that SHALL be included for vulnerability scanning is the XCCDF benchmark, which expresses the checklist of the flaws to be checked for. Each rule in the XCCDF benchmark SHALL reference one of the following: •

An OVAL vulnerability definition. This definition SHALL be contained in an OVAL component, which holds definitions of vulnerability checks used by the checklist. An XCCDF benchmark’s rules MAY reference one or more OVAL vulnerability class definitions in an OVAL component.

•

An OCIL questionnaire. This questionnaire SHALL be contained in an OCIL component, which holds questionnaires that collect information that OVAL is not being used to collect. An example of OCIL use is to give step-by-step directions for manually examining a system for a vulnerability that cannot be detected with OVAL. In such a case, OCIL is used for capturing information collected using manual examination. An XCCDF benchmark’s rules MAY reference one or more OCIL questionnaires in an OCIL component.

•

An OVAL patch definition. This definition SHALL be contained in an OVAL component, which holds definitions for patch compliance checks. These checks may be needed if an organization includes patch verification in its vulnerability scanning activities. An XCCDF benchmark MAY reference an OVAL patch definition through a patches up-to-date rule in a manner consistent with Sec. 3.2.4.3.

Each XCCDF benchmark SHALL have at least one rule that references either an OVAL vulnerability class definition in an OVAL component or an OCIL questionnaire in an OCIL component. All OVAL components and OCIL components referenced by the XCCDF benchmark SHALL be included in the SCAP source data stream. If the XCCDF benchmark component references any CPE names, then the SCAP source data stream SHALL include a CPE component, which specifies the products or platforms of interest, and SHALL include one or more OVAL inventory class definitions in an OVAL component that contain the technical procedures for determining whether or not a specific target asset has a product or platform of interest.

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Technical Specification for SCAP Version 1.4

The @use-case attribute in the <ds:data-stream> element SHALL be set to “VULNERABILITY.” 5.3. Inventory Scanning SCAP content can be used to collect information on the software installed on systems. One example of how this could be used is to verify that a group of systems all have required security software programs installed. This could help verify compliance with technical security control requirements. Another example is to collect software inventory data on devices that are not directly connected to the enterprise network, such as smart phones. Inventory scanning can also be applied to collect information on the presence of software artifacts on systems, such as malware or characteristics of malware that indicate its presence. SCAP content authored for this purpose can be used to detect classes or categories of malware based on system states that may be common across multiple malware instances. For example, it is a common practice to reuse malware code while making modifications to address available detection methods or change propagation characteristics. It is also possible to author content that detects a specific instantiation of malware. For example, the hashing of files can be used to identify a malicious executable or library. The SCAP source data stream component that SHALL be included for inventory scanning is the XCCDF benchmark, which references the inventory checks and captures the results. Each rule in the XCCDF benchmark SHALL reference one of the following: •

An OVAL inventory definition. This definition SHALL be contained in an OVAL component, which holds definitions of technical procedures for determining whether or not a specific target asset has software (e.g., product, platform, malware) of interest. An XCCDF benchmark’s rules MAY reference one or more OVAL inventory class definitions in an OVAL component.

•

An OCIL questionnaire. This questionnaire SHALL be contained in an OCIL component, which holds questionnaires that collect information that OVAL is not being used to collect, such as posing questions to users or harvesting inventory information from an existing database. An XCCDF benchmark’s rules MAY reference one or more OCIL questionnaires in an OCIL component.

The @use-case attribute in the <ds:data-stream> element SHALL be set to “INVENTORY.”

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Technical Specification for SCAP Version 1.4

Appendix A. Security Considerations Major security considerations for this version of SCAP include the following: •

Confidentiality. SCAP does not define any mechanisms for protecting the confidentiality of SCAP content or results. Organizations can add on such protections as they deem appropriate, such as encrypting results files that contain sensitive information regarding system vulnerabilities.

•

Malicious content. While SCAP provides mechanisms for ensuring the integrity of SCAP content and verifying content signatures, SCAP does not have any features specifically for handling malicious SCAP content (e.g., benchmarks, tailoring files). At a minimum, organizations should generate signatures for their content and verify the signatures on all content before using it to ensure that the content has not been maliciously altered. Additionally, organizations should not process content that fails validation and may choose not to use any content that has not been signed for stronger assurance.

•

Security value of content. Assertions or assessments regarding the security value of SCAP checklists and other forms of SCAP content is outside of the scope of SCAP’s capabilities. People and organizations may determine security values through their own methods (e.g., applying checklists to test systems and evaluating the results of those tests), but SCAP itself does not have any way of ensuring the security value of its content.

•

Component security. SCAP does not impose any additional security requirements on these on components that use SCAP (e.g., protocols, specifications, standards).

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Technical Specification for SCAP Version 1.4

Appendix B. List of Symbols, Abbreviations, and Acronyms Selected acronyms and abbreviations used in the guide are defined below. AI Asset Identification API Application Programming Interface ARF Asset Reporting Format CCE Common Configuration Enumeration CCSS Common Configuration Scoring System CPE Common Platform Enumeration CVE Common Vulnerabilities and Exposures CVSS Common Vulnerability Scoring System DHS Department of Homeland Security DoD Department of Defense DSIG Digital Signature FISMA Federal Information Security Modernization Act IR Interagency Report IT Information Technology ITL Information Technology Laboratory NIST National Institute of Standards and Technology NVD National Vulnerability Database OASIS Organization for the Advancement of Structured Information Standards

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Technical Specification for SCAP Version 1.4

OCIL Open Checklist Interactive Language OMB Office of Management and Budget OS Operating System OVAL Open Vulnerability and Assessment Language PCI Payment Card Industry RFC Request for Comments SCAP Security Content Automation Protocol SP Special Publication TMSAD Trust Model for Security Automation Data URI Uniform Resource Identifier URL Uniform Resource Locator XCCDF Extensible Configuration Checklist Description Format XML Extensible Markup Language

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Technical Specification for SCAP Version 1.4

Appendix C. Glossary This appendix contains definitions for selected terms used within the document. component schema The schema for an SCAP component specification (e.g. XCCDF, CPE, CVSS). Within this document, this term is distinct from “OVAL component schema,” which is defined by the OVAL specification. component specification One of the individual specifications that comprises SCAP. content consumer A product that accepts existing SCAP source data stream content, processes it, and produces SCAP result data streams content producer A product that generates SCAP source data stream content. globally unique identifier An identifier formatted following special conventions to support uniqueness within an organization and across all organizations creating identifiers. See Sec. 3.1.3 for the conventions. result content Part or all of one or more SCAP result data streams. Security Content Automation Protocol (SCAP) A suite of specifications that standardize the format and nomenclature by which software flaw and security configuration information is communicated to machines and humans. SCAP component A logical unit of data expressed using one or more of the SCAP component specifications. SCAP-conformant A product or SCAP data stream that meets the requirements of this specification. SCAP content Part or all of one or more SCAP data streams. SCAP data stream A specific instantiation of SCAP content. SCAP data stream collection A container for SCAP data streams and components. SCAP result data stream An SCAP data stream that holds output (result) content. SCAP source data stream An SCAP data stream that holds input (source) content. SCAP source data stream collection A container for SCAP data streams and components. SCAP use case A pre-defined way in which a product can use SCAP. See Sec. 5 for the definitions of the SCAP use cases.

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Technical Specification for SCAP Version 1.4

source content Part or all of SCAP source data streams. stream component A major element of a data stream, such as an XCCDF benchmark or a set of OVAL definitions. well-formed An SCAP-conformant data stream or stream component.

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Technical Specification for SCAP Version 1.4

Appendix D. Normative References This appendix provides normative references to the specifications that are required to implement the SCAP 1.4 components. See the annex for normative references to the XML and Schematron schema locations related to these specifications. Table 24 lists the normative references to specifications. Table 24. Specification locations Abbreviation

[AI] [ARF] [CCE] [CCSS] [CPE] [CPE-D] [CPE-L] [CPE-M] [CPE-N] [CVE] [CVSS-2.0] [CVSS-3.0] [CVSS-3.1] [CVSS-4.0] [DCES]

Name

[DSIG] [OCIL] [OVAL] [RFC2119] [RFC3986] [SCHEMATRON]

Asset Identification ARF CCE CCSS CPE CPE Dictionary CPE Applicability Language CPE Name Matching CPE Naming CVE CVSS 2.0 CVSS 3.0 CVSS 3.1 CVSS 4.0 Dublin Core metadata version 1.1 DSIG OCIL OVAL RFC 2119 RFC 3986 ISO/IEC 19757-3:2020

[SP800-126A] [TMSAD] [XCCDF]

NIST SP 800-126A TMSAD XCCDF

[XINCLUDE] [XLINK] [XMLCAT]

XInclude specification XLink specification XML Catalog specification

[XMLS]

W3C XML Schema

URL

https://doi.org/10.6028/NIST.IR.7693 https://doi.org/10.6028/NIST.IR.7694 https://ncp.nist.gov/cce https://doi.org/10.6028/NIST.IR.7502 See [CPE-D], [CPE-L], [CPE-M], and [CPE-N] https://doi.org/10.6028/NIST.IR.7697 https://doi.org/10.6028/NIST.IR.7698 https://doi.org/10.6028/NIST.IR.7696 https://doi.org/10.6028/NIST.IR.7695 https://cve.org/ https://www.first.org/cvss/v2/ https://www.first.org/cvss/v3.0/specification-document https://www.first.org/cvss/v3.1/specification-document https://www.first.org/cvss/v4.0/specification-document http://dublincore.org/documents/2012/06/14/dces/ https://www.w3.org/TR/xmldsig-core/ https://doi.org/10.6028/NIST.IR.7692 https://github.com/OVAL-Community/OVAL https://doi.org/10.17487/RFC2119 https://doi.org/10.17487/RFC3986 https://www.iso.org/obp/ui/#iso:std:iso-iec:19757:-3:ed3:v1:en https://doi.org/10.6028/NIST.SP.800-126A https://doi.org/10.6028/NIST.IR.7802 https://csrc.nist.gov/CSRC/media/Publications/nistir/7275/re v-4/final/documents/nistir-7275r4_updated-march2012_clean.pdf https://www.w3.org/TR/2006/REC-xinclude-20061115/ https://www.w3.org/TR/2001/REC-xlink-20010627/ https://www.oasisopen.org/committees/download.php/14809/xmlcatalogs.html https://www.w3.org/TR/2004/REC-xmlschema-1-20041028/, https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/

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Technical Specification for SCAP Version 1.4

Appendix E. Change Log Revision 4 Release 1 – June 2026 • • • • •

Updated all references of SCAP 1.3 to SCAP 1.4 Removed backward compatibility requirements for SCAP 1.1 and 1.0 Revised digital signature requirements Removed SWID requirements Removed references to OVAL ‘core’ and ‘platform’ schema versions

NIST SP 800-126r4: Technical Specification for the Security Content Automation Protocol (SCAP): SCAP Version 1.4

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