MediaWiki before 1.15.2 does not prevent wiki editors from linking to images from other web sites in wiki pages, which allows editors to obtain IP addresses and other information of wiki users by adding a link to an image on an attacker-controlled web site, aka "CSS validation issue."

Cross-site scripting (XSS) vulnerability in the Special:Block implementation in the getContribsLink function in SpecialBlockip.php in MediaWiki 1.14.0 and 1.15.0 allows remote attackers to inject arbitrary web script or HTML via the ip parameter.