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.
Fix
Patch, vendor advisory and mitigation references on NVD 1
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.3 · cure53NVD modified 2026-10-24 13:10
Affected (CPE criteria) 1
cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*
References 4
- https://github.com/cure53/DOMPurify/commit/7996f1dc78eb8b7922388aed75d94a9f8fad9a36 Patch
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcm Exploit, Third Party Advisory
- https://www.vulncheck.com/advisories/dompurify-before-hook-mutation-pollution-via-allowedtags Third Party Advisory
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcm Exploit, Third Party Advisory