DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. In 3.4.4, DOMPurify allowed selectedcontent by default, allowing browsers to re-clone an XSS payload after sanitization so that unsanitized markup inside <selectedcontent> is returned. This issue is fixed in version 3.4.5.
https://github.com/cure53/DOMPurify/security/advisories/GHSA-87xg-pxx2-7hvx
https://github.com/cure53/DOMPurify/releases/tag/3.4.5
https://github.com/cure53/DOMPurify/commit/011b0c78f2a0f57ee54f5fcccb697a46ca6e63ea