CVE-2026-83611

Description

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 version 0.6.0 and earlier, DOMParser.parseFromString() can silently accept an end tag such as </a\njunk>, close the element, and discard the trailing content. On 0.9.x, the lib/sax.js end-tag validator inherits the multiline flag from reg(), allowing the first line to satisfy the anchored XML ETag production; older lines have no equivalent residue validation. This parser differential can bypass a parse-before-trust well-formedness gate, although it does not inject the discarded content; onError on 0.9.x and errorHandler on 0.8.x are the relevant reporting interfaces. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

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Weakness Type (CWE)

CWE-1286 CWE-1286

References

Other References

https://github.com/xmldom/xmldom/commit/4430189660b0d380ee9c9ee7550a1358688e8828 https://github.com/xmldom/xmldom/commit/7b2ec67e1750daadd0bb06c92e875e726544a362 https://github.com/xmldom/xmldom/pull/1071 https://github.com/xmldom/xmldom/pull/1072 https://github.com/xmldom/xmldom/releases/tag/0.8.15 https://github.com/xmldom/xmldom/releases/tag/0.9.12 https://github.com/xmldom/xmldom/security/advisories/GHSA-6h8r-xr42-gp59 https://github.com/xmldom/xmldom/security/advisories/GHSA-6h8r-xr42-gp59

Frequently Asked Questions

What is CVE-2026-83611? +

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 version 0.6.0 and earlier, DOMParser.parseFromString() can silently accept an end tag such as </a\njunk>, close the element, and discard the trailing content. On 0.9.x, the lib/sax.js end-tag validator inherits the multiline flag from reg(), allowing the first line to satisfy the anchored XML ETag production; older lines have no equivalent residue validation. This parser differential can bypass a parse-before-trust well-formedness gate, although it does not inject the discarded content; onError on 0.9.x and errorHandler on 0.8.x are the relevant reporting interfaces. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

How do I check if I'm vulnerable to CVE-2026-83611? +

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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