UBUNTU-CVE-2026-41240

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 Metrics

• v4.0•MEDIUM•Score: 6CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
• v3.1•MEDIUM•Score: 6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected Systems

• ubuntu•node-dompurify

  all | all | all | all

References (3)

• https://ubuntu.com/security/CVE-2026-41240
• https://www.cve.org/CVERecord?id=CVE-2026-41240
• https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4m