xmldom: requireWellFormed DocType publicId/systemId validation is bypassable via an embedded line terminator (CVE-2026-83618) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-83618

xmldom: requireWellFormed DocType publicId/systemId validation is bypassable via an embedded line terminator

Answer in brief

CVE-2026-83618 records a Unknown severity vulnerability in xmldom: requireWellFormed DocType publicId/systemId validation is bypassable via an embedded line terminator. The current sources do not mark it as known exploited. The current feed maps xmldom/xmldom (generic), @xmldom/xmldom (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 1, 2026Updated Sep 1, 2026Source checked Sep 1, 2026First seen by HOL Sep 1, 2026Material review Sep 1, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps xmldom/xmldom (generic), @xmldom/xmldom (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
xmldom/xmldomgeneric	>= 0.9.10, < 0.9.12	Not reported
@xmldom/xmldomgeneric	>= 0.9.10, < 0.9.12	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for xmldom/xmldom, @xmldom/xmldom.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 1, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.