Vulnerability Description
DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAGS is used. Commit c361baa added an early exit for FORBID_ATTR at line 1214. The same fix was not applied to FORBID_TAGS. At line 1118-1123, when EXTRA_ELEMENT_HANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBID_TAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches the issue.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cure53 | Dompurify | < 3.4.0 |
Related Weaknesses (CWE)
References
- https://github.com/cure53/DOMPurify/commit/c361baa18dbdcb3344a41110f4c48ad85bf48Patch
- https://github.com/cure53/DOMPurify/releases/tag/3.4.0ProductRelease Notes
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4mExploitMitigationPatch
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4mExploitMitigationPatch
FAQ
What is CVE-2026-41240?
CVE-2026-41240 is a vulnerability with a CVSS score of 6.1 (MEDIUM). DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAG...
How severe is CVE-2026-41240?
CVE-2026-41240 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-41240?
Check the references section above for vendor advisories and patch information. Affected products include: Cure53 Dompurify.