CVE-2026-83606
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.30% probability · 23th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-1333
- Source
- security-advisories@github.com
References
- https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e
- https://github.com/xmldom/xmldom/pull/1039
- https://github.com/xmldom/xmldom/releases/tag/0.9.11
- https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7
- https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.