Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M
CVE-2026-83606xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions
High 8.7
In plain English
A high-severity uncontrolled resource consumption in xmldom from xmldom. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% 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 0.9.0-beta.9 until 0.9.11, the processing-instruction production in lib/grammar.js lets the greedy S+ separator and lazy Char*? data group repeatedly repartition a long whitespace tail when the required closing ?> is absent. Both parsePI and parseProcessingInstruction apply the expression to the entire remaining source, causing quadratic backtracking during DOMParser.parseFromString() under default options and allowing a small unauthenticated XML input to stall the Node.js event loop. This issue is fixed in @xmldom/xmldom version 0.9.11.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-xmldom | no fix listed | DEBIAN-CVE-2026-83606 |
| Debian:13 | node-xmldom | no fix listed | DEBIAN-CVE-2026-83606 |
| Debian:14 | node-xmldom | 0.9.11-1 | DEBIAN-CVE-2026-83606 |
| Ubuntu:22.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83606 |
| Ubuntu:24.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83606 |
| Ubuntu:26.04:LTS | node-xmldom | no fix listed | UBUNTU-CVE-2026-83606 |
| npm | @xmldom/xmldom | 0.9.11 | GHSA-g53g-w8rj-fmg7 |
Affected products (as reported)
Weakness: CWE-400, CWE-1333 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7 x_refsource_CONFIRM
- https://github.com/xmldom/xmldom/pull/1039 x_refsource_MISC
- https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e x_refsource_MISC
- https://github.com/xmldom/xmldom/releases/tag/0.9.11 x_refsource_MISC