CVE-2026-83611 — xmldom: Parser silently accepts a not-well-formed end tag whose name is followed by a line break and trailing content

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
xmldom / xmldom	affected <= 0.6.0
@xmldom / xmldom	affected >= 0.9.0, < 0.9.12; affected >= 0.7.0, < 0.8.15

CWE

CWE-1286

References

ADP enrichment

CISA-ADP

No English description supplied.

https://github.com/xmldom/xmldom/security/advisories/GHSA-6h8r-xr42-gp59