The (1) Special:Preferences and (2) Special:UserLogin pages in MediaWiki before 1.19.20, 1.22.x before 1.22.12 and 1.23.x before 1.23.5 allows remote authenticated users to conduct cross-site scripting (XSS) attacks or have unspecified other impact via crafted CSS, as demonstrated by modifying MediaWiki:Common.css.
Cross-site scripting (XSS) vulnerability in MediaWiki before 1.19.19, 1.22.x before 1.22.11, and 1.23.x before 1.23.4 allows remote attackers to inject arbitrary web script or HTML via a crafted SVG file.
Cross-site scripting (XSS) vulnerability in includes/actions/InfoAction.php in MediaWiki before 1.21.9 and 1.22.x before 1.22.6 allows remote attackers to inject arbitrary web script or HTML via the sort key in an info action.