Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M

CVE-2026-83605xmldom: Attribute name injection via setAttribute() bypasses requireWellFormed

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 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.6%top 50.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.14 and 0.9.11, and in xmldom version 0.6.0 and earlier, Element.setAttribute() calls the private _createAttribute(name) path without validating the attribute name, while Document.createAttribute(name) validates against QName. XMLSerializer.serializeToString() emits attribute names verbatim, and requireWellFormed: true did not validate them, so a crafted name can terminate the intended attribute and inject additional attributes, including event handlers, into browser-consumed output; synthesized xmlns:PREFIX declarations expose the same unchecked-name boundary. This issue is fixed in @xmldom/xmldom versions 0.8.14 and 0.9.11; no fixed version is available for xmldom.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	node-xmldom	no fix listed	DEBIAN-CVE-2026-83605
Debian:13	node-xmldom	no fix listed	DEBIAN-CVE-2026-83605
Debian:14	node-xmldom	0.9.11-1	DEBIAN-CVE-2026-83605
Ubuntu:22.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83605
Ubuntu:24.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83605
Ubuntu:26.04:LTS	node-xmldom	no fix listed	UBUNTU-CVE-2026-83605
npm	@xmldom/xmldom	0.8.14	GHSA-4w3w-2rp5-g8jm
npm	@xmldom/xmldom	0.9.11	GHSA-4w3w-2rp5-g8jm
npm	xmldom	no fix listed	GHSA-4w3w-2rp5-g8jm

Affected products (as reported)

Vendor	Product	Versions
xmldom	xmldom	<= 0.6.0
@xmldom	xmldom	>= 0.7.0, < 0.8.14>= 0.9.0, < 0.9.11

Weakness: CWE-91 · 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-4w3w-2rp5-g8jm x_refsource_CONFIRM
https://github.com/xmldom/xmldom/pull/1043 x_refsource_MISC
https://github.com/xmldom/xmldom/pull/1050 x_refsource_MISC
https://github.com/xmldom/xmldom/commit/cba1321218b069182695813fa7565653708e172e x_refsource_MISC
https://github.com/xmldom/xmldom/commit/d8212e632507eaf1d9f609657dd4c56abeb12d44 x_refsource_MISC
https://github.com/xmldom/xmldom/releases/tag/0.8.14 x_refsource_MISC
https://github.com/xmldom/xmldom/releases/tag/0.9.11 x_refsource_MISC