CVE-2026-83612: DoS

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.

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Weakness Type (CWE)

CWE-178 CWE-178

CWE-400 Uncontrolled Resource Consumption

References

Other References

https://github.com/xmldom/xmldom/commit/7ced40c06c28d151e996a97045018c3559ae4707 https://github.com/xmldom/xmldom/pull/1071 https://github.com/xmldom/xmldom/releases/tag/0.9.12 https://github.com/xmldom/xmldom/security/advisories/GHSA-6mj3-qw4j-hgrw https://github.com/xmldom/xmldom/security/advisories/GHSA-6mj3-qw4j-hgrw

Frequently Asked Questions

What is CVE-2026-83612? +

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.

How do I check if I'm vulnerable to CVE-2026-83612? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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