CVE-2026-41238

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions 3.0.1 through 3.3.3 are vulnerable to a prototype pollution-based XSS bypass. When an application uses `DOMPurify.sanitize()` with the default configuration (no `CUSTOM_ELEMENT_HANDLING` option), a prior prototype pollution gadget can inject permissive `tagNameCheck` and `attributeNameCheck` regex values into `Object.prototype`, causing DOMPurify to allow arbitrary custom elements with arbitrary attributes — including event handlers — through sanitization. Version 3.4.0 fixes the issue.

CVSS 3.1

6.9CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 13% of CVEs (scores of 2026-10-26)

CWEs

CWE-79, CWE-1321

Published

2026-04-23

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Packages (OSV)

References

• https://github.com/cure53/DOMPurify/releases/tag/3.4.0
• https://github.com/cure53/DOMPurify/security/advisories/GHSA-v9jr-rg53-9pgp
• https://github.com/cure53/DOMPurify/security/advisories/GHSA-v9jr-rg53-9pgp

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