Cross-site request forgery (CSRF) vulnerability in api/ApiQueryCheckUser.php in the CheckUser extension for MediaWiki, possibly Checkuser before 2.3, allows remote attackers to hijack the authentication of arbitrary users for requests that "perform sensitive write actions" via unspecified vectors.
https://exchange.xforce.ibmcloud.com/vulnerabilities/86893
https://bugzilla.wikimedia.org/show_bug.cgi?id=45019
http://www.securityfocus.com/bid/62210
http://seclists.org/oss-sec/2013/q3/553
http://lists.wikimedia.org/pipermail/mediawiki-announce/2013-September/000133.html