CVE-2026-66010

DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING

Published: Jul 24, 2026Updated: Aug 6, 2026 Sources: CVE List NVDCWE-79

6.1MEDIUM

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:RUser Interaction

Required

Scope

S:CScope

Changed

Impact

C:LConfidentiality

Low

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-79

Affected Products

cure53

aka dompurify

DOMPurifyLibrary

OSS Libraries / generic-library

and 1 more affected products View all →

Exploitability

Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Execution

Initial Access

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References

https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4

github.com

https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling

vulncheck.com

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