CVE-2026-41240

MEDIUM

DOMPurify: FORBID_TAGS bypassed by function-based ADD_TAGS predicate (asymmetry with FORBID_ATTR fix)

Title source: cna

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.

References (3)

[X_Refsource_Confirm] https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4m

[X_Refsource_Misc] https://github.com/cure53/DOMPurify/commit/c361baa18dbdcb3344a41110f4c48ad85bf48f80

View Writeup ZIP pw:eip

[X_Refsource_Misc] https://github.com/cure53/DOMPurify/releases/tag/3.4.0

Scores

CVSS v4 6.0

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

Details

CWE

CWE-183 CWE-79

Status published

Products (1)

cure53/DOMPurify < 3.4.0

Published Apr 23, 2026

Tracked Since Apr 23, 2026