Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M
CVE-2026-83611xmldom: Parser silently accepts a not-well-formed end tag whose name is followed by a line break and trailing content
Medium 6.9
In plain English
A medium-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 50% 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. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, DOMParser.parseFromString() can silently accept an end tag such as </a\njunk>, close the element, and discard the trailing content. On 0.9.x, the lib/sax.js end-tag validator inherits the multiline flag from reg(), allowing the first line to satisfy the anchored XML ETag production; older lines have no equivalent residue validation. This parser differential can bypass a parse-before-trust well-formedness gate, although it does not inject the discarded content; onError on 0.9.x and errorHandler on 0.8.x are the relevant reporting interfaces. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; 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-2026-83611 |
| Debian:13 | node-xmldom | no fix listed | DEBIAN-CVE-2026-83611 |
| Debian:14 | node-xmldom | 0.9.12-1 | DEBIAN-CVE-2026-83611 |
| Ubuntu:22.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83611 |
| Ubuntu:24.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83611 |
| Ubuntu:26.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83611 |
| Ubuntu:26.10 | node-xmldom | no fix listed | UBUNTU-CVE-2026-83611 |
| npm | @xmldom/xmldom | 0.8.15 | GHSA-6h8r-xr42-gp59 |
| npm | @xmldom/xmldom | 0.9.12 | GHSA-6h8r-xr42-gp59 |
| npm | xmldom | no fix listed | GHSA-6h8r-xr42-gp59 |
Affected products (as reported)
Weakness: CWE-1286 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/xmldom/xmldom/security/advisories/GHSA-6h8r-xr42-gp59 x_refsource_CONFIRM
- https://github.com/xmldom/xmldom/pull/1071 x_refsource_MISC
- https://github.com/xmldom/xmldom/pull/1072 x_refsource_MISC
- https://github.com/xmldom/xmldom/commit/4430189660b0d380ee9c9ee7550a1358688e8828 x_refsource_MISC
- https://github.com/xmldom/xmldom/commit/7b2ec67e1750daadd0bb06c92e875e726544a362 x_refsource_MISC
- https://github.com/xmldom/xmldom/releases/tag/0.8.15 x_refsource_MISC
- https://github.com/xmldom/xmldom/releases/tag/0.9.12 x_refsource_MISC