CVE-2026-83607
The requireWellFormed: true path did not validate the element qualified name or synthesized xmlns:PREFIX declaration, so attacker-controlled tag names could inject attributes, elements, or processing instructions into serialized XML or HTML and could…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.61%). 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. Prior to @xmldom/xmldom versions 0.8.14 and 0.9.11, and in xmldom version 0.6.0 and earlier, Document.createElement(tagName) stores an unvalidated element name and XMLSerializer.serializeToString() emits that name verbatim. The requireWellFormed: true path did not validate the element qualified name or synthesized xmlns:PREFIX declaration, so attacker-controlled tag names could inject attributes, elements, or processing instructions into serialized XML or HTML and could cause cross-site scripting when browser-consumed. The unchecked values violate the XML QName constraint, and default serialization and creation-time createElement() behavior remain permissive. This issue is fixed in @xmldom/xmldom versions 0.8.14 and 0.9.11; no fixed version is available for xmldom.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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
- 0.61% probability · 49th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-91
- Source
- security-advisories@github.com
EPSS 0.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/xmldom/xmldom/commit/cba1321218b069182695813fa7565653708e172e
- https://github.com/xmldom/xmldom/commit/d8212e632507eaf1d9f609657dd4c56abeb12d44
- https://github.com/xmldom/xmldom/pull/1043
- https://github.com/xmldom/xmldom/pull/1050
- https://github.com/xmldom/xmldom/releases/tag/0.8.14
- https://github.com/xmldom/xmldom/releases/tag/0.9.11
- https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj
- https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.