CVE-2026-41240

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.

Score

CVSS 3.1 6.1 Medium

Status

Analyzed - security-advisories@github.com

Published

2026-04-23

Last modified

2026-10-26

Weaknesses

CWE-183, CWE-79

Affected products

• Dompurify (Cure53)

References

• https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4m
• https://github.com/cure53/DOMPurify/commit/c361baa18dbdcb3344a41110f4c48ad85bf48f80
• https://github.com/cure53/DOMPurify/releases/tag/3.4.0