Multiple cross-site scripting (XSS) vulnerabilities in MediaWiki before 1.4.9 allow remote attackers to inject arbitrary web script or HTML via (1) <math> tags or (2) Extension or <nowiki> sections that "bypass HTML style attribute restrictions" that are intended to protect against XSS vulnerabilities in Internet Explorer clients.
http://sourceforge.net/project/shownotes.php?release_id=352777