CVE-2026-66010: DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING

Published Jul 24, 2026
·
Updated

DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOMELEMENTHANDLING.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.

Affected Software

6 affected components
DOMPurify<3.4.12
Cure53 DOMPurify<3.4.12
IBM i<=7.6
IBM i<=7.5
IBM i<=7.4
IBM i<=7.3

Event History

Jul 24, 2026
CVE Published
via MITRE·12:07 PM
Data Sourced
via MITRE·12:07 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·01:18 PM
DescriptionSeverityWeaknessAffected Software
Aug 11, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-66010?

The severity of CVE-2026-66010 is classified as medium with a score of 6.1.

2

How do I fix CVE-2026-66010?

To fix CVE-2026-66010, upgrade DOMPurify to version 3.4.12 or later.

3

What type of vulnerability is CVE-2026-66010?

CVE-2026-66010 is a Cross-Site Scripting (XSS) vulnerability.

4

What impact does CVE-2026-66010 have?

CVE-2026-66010 allows attackers to bypass application security policies and preserve sensitive attributes in custom elements.

5

What software is affected by CVE-2026-66010?

The affected software for CVE-2026-66010 is DOMPurify, specifically versions before 3.4.12.

Company

Resources

Contact

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