Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M

CVE-2026-83609xmldom: Creation-time XML Name/QName validation is bypassable via an embedded line terminator, allowing injection on the default serialization path

High 8.7

In plain English

A high-severity security flaw in xmldom from xmldom. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.5%top 54.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0 until 0.9.12, the shared reg() builder in lib/grammar.js compiles the anchored QName_exact validator with the multiline flag, so ^ and $ validate only one line instead of the complete name. createElementNS, createAttributeNS, createDocumentType, and createAttribute consequently accept a malformed XML name whose first line is valid and whose later text injects markup when serialized through either the default path or requireWellFormed: true. The triggering ECMAScript line terminators are U+000A, U+000D, U+2028, and U+2029. 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-2026-83609
Debian:13	node-xmldom	no fix listed	DEBIAN-CVE-2026-83609
Debian:14	node-xmldom	0.9.12-1	DEBIAN-CVE-2026-83609
Ubuntu:22.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83609
Ubuntu:24.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83609
Ubuntu:26.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83609
Ubuntu:26.10	node-xmldom	no fix listed	UBUNTU-CVE-2026-83609
npm	@xmldom/xmldom	0.9.12	GHSA-3px3-54cx-rmw9

Affected products (as reported)

Vendor	Product	Versions
xmldom	xmldom	>= 0.9.0, < 0.9.12
@xmldom	xmldom	>= 0.9.0, < 0.9.12

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-3px3-54cx-rmw9 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