Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M
CVE-2026-83617xmldom: requireWellFormed element/attribute name validation is bypassable via an embedded line terminator
High 8.7
In plain English
A high-severity security flaw in xmldom from xmldom. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-xmldom | no fix listed | DEBIAN-CVE-2026-83617 |
| Debian:13 | node-xmldom | no fix listed | DEBIAN-CVE-2026-83617 |
| Debian:14 | node-xmldom | 0.9.12-1 | DEBIAN-CVE-2026-83617 |
| Ubuntu:22.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83617 |
| Ubuntu:24.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83617 |
| Ubuntu:26.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83617 |
| Ubuntu:26.10 | node-xmldom | no fix listed | UBUNTU-CVE-2026-83617 |
| npm | @xmldom/xmldom | 0.9.12 | GHSA-jxjr-3g7g-3944 |
Affected products (as reported)
Weakness: CWE-91, CWE-625 · Vector: 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
References
- https://github.com/xmldom/xmldom/security/advisories/GHSA-jxjr-3g7g-3944 x_refsource_CONFIRM
- https://github.com/xmldom/xmldom/pull/1071 x_refsource_MISC
- https://github.com/xmldom/xmldom/commit/7b2ec67e1750daadd0bb06c92e875e726544a362 x_refsource_MISC
- https://github.com/xmldom/xmldom/releases/tag/0.9.12 x_refsource_MISC