Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26870
Reference (s):
- https://github.com/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d
- URL: https://github.com/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d
- https://github.com/cure53/DOMPurify/compare/2.0.16 2.0.17
- URL: https://github.com/cure53/DOMPurify/compare/2.0.16 2.0.17
- https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/