DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback
Summary
DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback
Original description
The description as published by the source.
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.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-41238 node-dompurify
- Ubuntu UBUNTU-CVE-2026-41238 node-dompurify
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web github.com