Cross-site scripting (XSS) vulnerability in MediaWiki before 1.4.2, when using HTML Tidy ($wgUseTidy), allows remote attackers to inject arbitrary web script or HTML via unknown vectors.
MediaWiki 1.3.8 and earlier, when used with Apache mod_mime, does not properly handle files with two file extensions, such as .php.rar, which allows remote attackers to upload and execute arbitrary code.