# CVE-2026-83617

## Summary

- **CVE ID:** CVE-2026-83617
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-91, CWE-625
- **Published:** Sep 1, 2026
- **Last Modified:** Sep 1, 2026

## 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.

## Affected Products

- xmldom — xmldom (>= 0.9.11, < 0.9.12)
- @xmldom — xmldom (>= 0.9.11, < 0.9.12)

## References

- [CNA](https://github.com/xmldom/xmldom/security/advisories/GHSA-jxjr-3g7g-3944)
- [CNA](https://github.com/xmldom/xmldom/pull/1071)
- [CNA](https://github.com/xmldom/xmldom/commit/7b2ec67e1750daadd0bb06c92e875e726544a362)
- [CNA](https://github.com/xmldom/xmldom/releases/tag/0.9.12)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.33%
- **EPSS Percentile:** 25.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._