An issue was discovered in the ArticleRatings extension for MediaWiki through 1.42.1. Special:ChangeRating allows CSRF to alter data via a GET request.
An issue was discovered in includes/specials/SpecialMovePage.php in MediaWiki before 1.39.7, 1.40.x before 1.40.3, and 1.41.x before 1.41.1. If a user with the necessary rights to move the page opens Special:MovePage for a page with tens of thousands of subpages, then the page will exceed the maximum request time, leading to a denial of service.
An issue was discovered in includes/CommentFormatter/CommentParser.php in MediaWiki before 1.39.7, 1.40.x before 1.40.3, and 1.41.x before 1.41.1. XSS can occur because of mishandling of the 0x1b character, as demonstrated by Special:RecentChanges#%1b0000000.
An issue was discovered in the Phonos extension in MediaWiki before 1.40.2. PhonosButton.js allows i18n-based XSS via the phonos-purge-needed-error message.
An issue was discovered in the GlobalBlocking extension in MediaWiki before 1.40.2. For a Special:GlobalBlock?uselang=x-xss URI, i18n-based XSS can occur via the parentheses message. This affects subtitle links in buildSubtitleLinks.