CVE-2026-34601: xmldom: XML injection via unsafe CDATA serialization allows attacker-controlled markup insertion
(updated )
@xmldom/xmldom allows attacker-controlled strings containing the CDATA terminator ]]> to be inserted into a CDATASection node. During serialization, XMLSerializer emitted the CDATA content verbatim without rejecting or safely splitting the terminator. As a result, data intended to remain text-only became active XML markup in the serialized output, enabling XML structure
injection and downstream business-logic manipulation.
The sequence ]]> is not allowed inside CDATA content and must be rejected or safely handled during serialization. (MDN Web Docs)
References
- github.com/advisories/GHSA-wh4c-j3r5-mjhp
- github.com/xmldom/xmldom/commit/2b852e836ab86dbbd6cbaf0537f584dd0b5ac184
- github.com/xmldom/xmldom/releases/tag/0.8.12
- github.com/xmldom/xmldom/releases/tag/0.9.9
- github.com/xmldom/xmldom/security/advisories/GHSA-wh4c-j3r5-mjhp
- nvd.nist.gov/vuln/detail/CVE-2026-34601
Code Behaviors & Features
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