Permissive Regular Expression in xmldom - CVE-2026-83618
Published: August 25, 2026 / Updated: September 2, 2026
Vulnerability identifier: #VU145129
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-83618
CWE-ID: CWE-625
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject XML markup into the DOCTYPE declaration.
The vulnerability exists due to permissive regular expression validation in the requireWellFormed DocumentType publicId/systemId serializer check when processing a DocumentType with an embedded line terminator in publicId or systemId. A remote attacker can supply a crafted publicId or systemId value to inject XML markup into the DOCTYPE declaration.
Only the opt-in serialization path with requireWellFormed: true is affected.
Affected software
xmldom
How to mitigate CVE-2026-83618
Install security update from vendor's website.
xmldom - update to 0.9.12