CVE-2026-83612

xmldom: HTML raw-text closing-tag case mismatch causes output amplification

State: Published
Severity: 8.7 High
Published: Sep 1, 2026
Updated: Sep 1, 2026
Reserved: Aug 31, 2026

Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0-beta.1 until 0.9.12, HTML-mode parsing through DOMParser.parseFromString() mishandles a mixed-case closing tag for the script, style, textarea, or title raw-text elements. parseHtmlSpecialContent, selected by isHTMLRawTextElement or isHTMLEscapableRawTextElement, uses a case-sensitive indexOf() and then calls substring() with a missing-close result of negative one, causing unstable parser progression and quadratic output amplification. A small untrusted text/html document can consequently consume disproportionate CPU and memory when parsed and serialized. This issue is fixed in @xmldom/xmldom version 0.9.12.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-178 Improper Handling of Case Sensitivity
CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
xmldomxmldom	>= 0.9.0-beta.1, < 0.9.12Affected
xmldom@xmldom	>= 0.9.0-beta.1, < 0.9.12Affected

References

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