OWASP AntiSamy before 1.6.4 allows XSS via HTML attributes when using the HTML output serializer (XHTML is not affected). This was demonstrated by a javascript: URL with : as the replacement for the : character.
{ "urgency": "not yet assigned" }
"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-35043.json"