CVE-2026-41238 — MEDIUM (6.9)

Vulnerability Description

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 Score

6.9

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

HIGH

Integrity

LOW

Availability

NONE

Related Weaknesses (CWE)

CWE-79 CWE-1321

References

FAQ

What is CVE-2026-41238?

CVE-2026-41238 is a vulnerability with a CVSS score of 6.9 (MEDIUM). 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 `DOMPu...

How severe is CVE-2026-41238?

CVE-2026-41238 has been rated MEDIUM with a CVSS base score of 6.9/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-41238?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.