CVE-2026-66010

EUVD-2026-48582
DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
6.1 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
cure53dompurify
𝑥
< 3.4.12
CNA
Debian logo
Debian Releases
Debian Product
Codename
node-dompurify
bookworm
vulnerable
bookworm (security)
vulnerable
forky
3.4.12+dfsg-1
fixed
sid
3.4.12+dfsg-1
fixed
trixie
vulnerable
Common Weakness Enumeration
References
https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4
https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling
https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4