High 8.7Published Sep 1, 2026

CVE-2026-83606xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions

Updated under an hour ago (2026-10-19 07:20 UTC)

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Every CVE for xmldom

Exploited in the last 30 days

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.

CVSS: 8.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-400, CWE-1333
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

xmldom xmldom xmldom:xmldom (from the name)	from 0.9.0-beta.9, < 0.9.11	CNA record

References

https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7x-refsource-confirm
https://github.com/xmldom/xmldom/pull/1039x-refsource-misc
https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802ex-refsource-misc
https://github.com/xmldom/xmldom/releases/tag/0.9.11x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.