Cross-site scripting (XSS) vulnerability in contrib/example.php in the SyntaxHighlight GeSHi extension for MediaWiki, possibly as downloaded before September 2013, allows remote attackers to inject arbitrary web script or HTML via the PATH_INFO.
https://exchange.xforce.ibmcloud.com/vulnerabilities/86890
http://seclists.org/oss-sec/2013/q3/553
http://lists.wikimedia.org/pipermail/mediawiki-announce/2013-September/000133.html