CVE-2026-83617
CVE-2026-83617 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-91.
Key facts
- Severity: High (CVSS 4.0 base score 8.7)
- EPSS exploit prediction: 1% (45th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-91
- Published:
- Last modified:
Description
xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.11 until 0.9.12, the requireWellFormed: true element and attribute name checks use the anchored QName_exact expression produced by reg() in lib/grammar.js, which inherits the multiline flag. A name with a valid first line followed by U+000A, U+000D, U+2028, or U+2029 and breakout markup therefore passes validation and is emitted verbatim in element start and end tags or attribute names. This bypasses the strict-serialization checks introduced for the earlier element-name and attribute-name injection advisories, while the default serialization path remains outside the strict guarantee. This issue is fixed in @xmldom/xmldom version 0.9.12.
Frequently asked questions
- What is CVE-2026-83617?
- xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.11 until 0.9.12, the requireWellFormed: true element and attribute name checks use the anchored QName_exact expression produced by reg() in lib/grammar.js, which inherits the multiline flag. A name with a valid first line followed by U+000A, U+000D, U+2028, or U+2029 and breakout markup therefore passes validation and is emitted verbatim in element start and end tags or attribute names. This bypasses the strict-serialization checks introduced for the earlier element-name and attribute-name injection advisories, while the default serialization path remains outside the strict guarantee. This issue is fixed in @xmldom/xmldom version 0.9.12.
- How severe is CVE-2026-83617?
- CVE-2026-83617 has a CVSS 4.0 base score of 8.7, rated high severity.
- Is CVE-2026-83617 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-83617?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-83617 published?
- CVE-2026-83617 was published on 2026-09-01 and last updated on 2026-09-08.
References
- https://github.com/xmldom/xmldom/commit/7b2ec67e1750daadd0bb06c92e875e726544a362
- https://github.com/xmldom/xmldom/pull/1071
- https://github.com/xmldom/xmldom/releases/tag/0.9.12
- https://github.com/xmldom/xmldom/security/advisories/GHSA-jxjr-3g7g-3944
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