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.
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Fixes

Solution

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Workaround

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History

Tue, 01 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
First Time appeared Xmldom
Xmldom xmldom
Vendors & Products Xmldom
Xmldom xmldom
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 01 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
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.
Title xmldom: HTML raw-text closing-tag case mismatch causes output amplification
Weaknesses CWE-178
CWE-400
References
Metrics cvssV4_0

{'score': 8.7, 'vector': '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-01T15:30:10.060Z

Reserved: 2026-08-31T20:36:25.744Z

Link: CVE-2026-83612

cve-icon Vulnrichment

Updated: 2026-09-01T15:30:04.360Z

cve-icon NVD

Status : Received

Published: 2026-09-01T15:17:39.430

Modified: 2026-09-01T16:17:26.897

Link: CVE-2026-83612

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-01T17:00:17Z

Weaknesses