github.com
https://github.com/cure53/DOMPurify CVE-2026-41240
MEDIUM
DOMPurify: FORBID_TAGS bypassed by function-based ADD_TAGS predicate (asymmetry with FORBID_ATTR fix)
Record summary
CVE-2026-41240 has a selected CVSS score of 6.0 (medium).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationPoC
AutomatableNo
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Apr 23, 2026 · Source: CVE List
Affected products and versions
2| Product | Source | Version range | Status |
|---|---|---|---|
DOMPurifyBrowse cure53 / DOMPurify | CVE List | < 3.4.0 | affected |
dompurifyBrowse npm / dompurify | GitHub Advisory | Before 3.4.0 · Fixed in 3.4.0 | affected |
References
5github.com
https://github.com/cure53/DOMPurify/commit/c361baa18dbdcb3344a41110f4c48ad85bf48f80 github.com
https://github.com/cure53/DOMPurify/releases/tag/3.4.0 github.comConfirmation
https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4m nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-41240