An issue was discovered in MediaWiki before 1.37.3 and 1.38.x before 1.38.1. The contributions-title, used on Special:Contributions, is used as page title without escaping. Hence, in a non-default configuration where a username contains HTML entities, it won’t be escaped.
lists.debian.org/debian-lts-announce/2022/09/msg00027.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7N5ZBWLNNPZKFK7Q4KEHGCJ2YELQEUJP/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DKKOQXPYLMBSEVDHFS32BPBR3ZQJKY5B/
phabricator.wikimedia.org/T308473
security.gentoo.org/glsa/202305-24
www.debian.org/security/2022/dsa-5246