Helder

**Name of the Vulnerable Software and Affected Versions** MediaWiki versions prior to 1.19.20 MediaWiki versions 1.22.x prior to 1.22.12 MediaWiki versions 1.23.x prior to 1.23.5 **Description** The issue affects the Special:Preferences and Special:UserLogin pages in MediaWiki, allowing remote authenticated users to conduct cross-site scripting (XSS) attacks via crafted CSS. This can be demonstrated by modifying MediaWiki:Common.css, which can lead to unspecified other impact. **Recommendations** For MediaWiki versions prior to 1.19.20, update to version 1.19.20 or later. For MediaWiki versions 1.22.x prior to 1.22.12, update to version 1.22.12 or later. For MediaWiki versions 1.23.x prior to 1.23.5, update to version 1.23.5 or later.