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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Active

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact Low

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation poc

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
cure53 DOMPurify unaffected
Version Status Constraints
0 affected < 3.4.12
3.4.12 unaffected —

No data.

No data.

No data.

Project Subscriptions

Vendors Products
Cure53 Subscribe
Dompurify Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4 cve-icon cve-icon
https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling cve-icon
History

Fri, 24 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
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.
Title DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING
First Time appeared Cure53
Cure53 dompurify
Weaknesses CWE-79
CPEs cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*
Vendors & Products Cure53
Cure53 dompurify
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-07-24T14:14:08.456Z

Reserved: 2026-07-23T19:22:30.643Z

Link: CVE-2026-66010

cve-icon Vulnrichment

Updated: 2026-07-24T14:13:39.710Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses