CVE-2026-41238

Medium

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.

SeverityMedium

CVSS6.9

Exploit probability—

ProductDompurify

PublishedApr 23, 2026

First seenApr 23, 2026

Weakness typeCWE-79Cross-site scripting (XSS)CWE-1321Prototype pollution

How to fix

Update

dompurify3.4.0 or later

Affected products

Product	Affected versions	Fixed in
dompurifynpm	3.0.1 ≤ v < 3.4.0	3.4.0

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.