Cross-site scripting (XSS) vulnerability in MediaWiki 1.19.9 before 1.19.10, 1.2x before 1.21.4, and 1.22.x before 1.22.1 allows remote attackers to inject arbitrary web script or HTML via unspecified CSS values.
http://lists.wikimedia.org/pipermail/mediawiki-announce/2014-January/000138.html