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.
History

Wed, 29 Apr 2026 15:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N'}

cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}


Wed, 29 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N'}

threat_severity

Moderate


Tue, 28 Apr 2026 02:00:00 +0000

Type Values Removed Values Added
First Time appeared Cure53
Cure53 dompurify
Vendors & Products Cure53
Cure53 dompurify

Thu, 23 Apr 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 23 Apr 2026 15:45:00 +0000

Type Values Removed Values Added
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.
Title DOMPurify: FORBID_TAGS bypassed by function-based ADD_TAGS predicate (asymmetry with FORBID_ATTR fix)
Weaknesses CWE-183
CWE-79
References
Metrics cvssV4_0

{'score': 6, 'vector': '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-04-23T14:54:32.426Z

Updated: 2026-04-23T17:21:30.547Z

Reserved: 2026-04-18T03:47:03.135Z

Link: CVE-2026-41240

cve-icon Vulnrichment

Updated: 2026-04-23T17:21:16.648Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-23T16:16:26.710

Modified: 2026-04-29T14:58:30.117

Link: CVE-2026-41240

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-23T14:54:32Z

Links: CVE-2026-41240 - Bugzilla