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.
{ "cpes": [ "cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*", "cpe:2.3:a:mediawiki:mediawiki:1.38.0:-:*:*:*:*:*:*", "cpe:2.3:a:mediawiki:mediawiki:1.38.0:rc0:*:*:*:*:*:*", "cpe:2.3:a:mediawiki:mediawiki:1.38.0:rc1:*:*:*:*:*:*" ], "severity": "Medium" }