CVE-2026-83609

CVE-2026-83609 · xmldom: Creation-time XML Name/QName validation is bypassable via an embedded line terminator, allowing injection on the default serialization path

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xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0 until 0.9.12, the shared reg() builder in lib/grammar.js compiles the anchored QName_exact validator with the multiline flag, so ^ and $ validate only one line instead of the complete name. createElementNS, createAttributeNS, createDocumentType, and createAttribute consequently accept a malformed XML name whose first line is valid and whose later text injects markup when serialized through either the default path or requireWellFormed: true. The triggering ECMAScript line terminators are U+000A, U+000D, U+2028, and U+2029. This issue is fixed in @xmldom/xmldom version 0.9.12.

CVSS 8.7 · High · EPSS 0.5% · Fix available

Published

2026-09-01T14:29:40.475Z

Updated

2026-09-01T18:10:19.349Z

Stack: system · node

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