The TitleIcon extension for MediaWiki is vulnerable to stored XSS through the #titleicon_unicode parser function. User input passed to this function is wrapped in an HtmlArmor object without sanitization and rendered directly into the page header, allowing attackers to inject arbitrary JavaScript. This issue affects Mediawiki - TitleIcon extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
https://phabricator.wikimedia.org/T394721
https://gerrit.wikimedia.org/r/q/I2e8c73445172679634f6ec64d37cf82507dfa110
https://gerrit.wikimedia.org/r/q/I107ab638fecbf52b5bec3f02726ed24b1ae74429