DOMPurify Logic Error Allows Tag Bypass Affecting Web Security
CVE-2026-65903

5.1MEDIUM

Key Information:

Vendor

Cure53

Status
Dompurify
Vendor
CVE Published:
23 July 2026

What is CVE-2026-65903?

A logic error in the ADD_TAGS function of DOMPurify versions before 3.4.0 permits unauthorized tags to bypass the restrictions imposed by the FORBID_TAGS mechanism. This flaw enables attackers to inject potentially harmful tags into the sanitized output by crafting specific input that exploits this short-circuit evaluation, thereby undermining the integrity of web content security.

Affected Version(s)

DOMPurify 0 < 3.4.0

DOMPurify 3.4.0

References

https://github.com/cure53/DOMPurify/security/advisories/G...
vendor-advisory
https://www.vulncheck.com/advisories/dompurify-before-add...
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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