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xmldom: Quadratic-time parsing via the malformed-input recovery path — `parseElementStartPart` re-scan and `normalize()` adjacent-text merge

@xmldom xmldom · CVE-2026-83614
0 news outlets0 CERTs and agencies0 researchers

Assessment: Track

SSVC decision points: exploitation none, automatable yes, technical impact partial, deployment low.

What is it?

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom versions 0.3.0 through 0.6.0, two independent quadratic paths can cause denial of service. In lib/sax.js, parseElementStartPart repeatedly rescans a malformed tag name to the next > during single-character recovery; in lib/dom.js, normalize() repeatedly removes and appends adjacent text nodes, causing quadratic reindexing and string rebuilding. The first path is reachable through default DOMParser.parseFromString() processing, while the second is also reachable through a direct normalize() call on a programmatically constructed DOM, and endDocument invokes that normalization after parsing. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

Evidence

No coverage recorded yet.

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
8.7
EPSS
0.6%
First seen
7 d ago
Status
corroborated

All @xmldom vulnerabilities