Bug 2526855 (CVE-2026-83618)

Summary: CVE-2026-83618 xmldom: @xmldom/xmldom: xmldom: DocumentType injection bypass via embedded line terminators
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, sghai, sidsharm, suppawar, vlaad
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in xmldom, a JavaScript XML parser and serializer module. A remote attacker could bypass the `requireWellFormed` strict-serialization mitigation for DocumentType injection by embedding line terminators within the `publicId` or `systemId` of a DocumentType declaration. This allows for the injection of arbitrary markup into the XML output, potentially leading to data manipulation or other security impacts depending on how the XML is processed.
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Description OSIDB Bzimport 2026-09-01 15:14:44 UTC
xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.10 until 0.9.12, the requireWellFormed: true serializer validates DocumentType.publicId and DocumentType.systemId with PubidLiteral_match and SystemLiteral_match expressions produced by reg() in lib/grammar.js, which inherit the multiline flag. A complete valid literal on the first line can therefore satisfy the matcher while U+000A, U+000D, U+2028, or U+2029 and breakout markup remain in the emitted <!DOCTYPE ...> declaration. This bypasses the strict-serialization mitigation for the earlier DocumentType injection advisory; creation and direct property assignment remain unvalidated by design. This issue is fixed in @xmldom/xmldom version 0.9.12.