Description
DOMPurify before 3.4.7 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.
Affected products
cure53: dompurify
References4
- github.com/cure53/DOMPurify/commit/7996f1dc78eb8b7922388aed75d9… Patch
- github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-… ExploitThird Party Advisory
- github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-… ExploitThird Party Advisory
- www.vulncheck.com/advisories/dompurify-before-hook-mutation-pol… Third Party Advisory
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 30 · as of 14 November 2026
- CWE
- CWE-501
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