Vulnerability Description
DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes when sanitize is called without an explicit cfg.ALLOWED_TAGS / cfg.ALLOWED_ATTR array. A hook that mutates these fields permanently widens the default allow-lists for the lifetime of the DOMPurify instance, so all subsequent default-config sanitize calls inherit the widened defaults and attacker payloads using the poisoned tag/attribute name survive sanitization. removeAllHooks(), clearConfig(), and passing a fresh cfg do not recover the state; only constructing a new DOMPurify instance does.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cure53 | Dompurify | < 3.4.7 |
Related Weaknesses (CWE)
References
- https://github.com/cure53/DOMPurify/commit/7996f1dc78eb8b7922388aed75d94a9f8fad9Patch
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcmExploitThird Party Advisory
- https://www.vulncheck.com/advisories/dompurify-before-hook-mutation-pollution-viThird Party Advisory
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcmExploitThird Party Advisory
FAQ
What is CVE-2026-65902?
CVE-2026-65902 is a vulnerability with a CVSS score of 6.1 (MEDIUM). DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute...
How severe is CVE-2026-65902?
CVE-2026-65902 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-65902?
Check the references section above for vendor advisories and patch information. Affected products include: Cure53 Dompurify.