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.

CVSS 4.0

6.0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 23% of CVEs (scores of 2026-10-26)

CWEs

CWE-79, CWE-183

Published

2026-04-23

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• cure53:dompurify

Packages (OSV)

References

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

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