MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 uses weak random numbers for password reset tokens, which makes it easier for remote attackers to change the passwords of arbitrary users.
https://exchange.xforce.ibmcloud.com/vulnerabilities/78910
https://bugzilla.wikimedia.org/show_bug.cgi?id=35078
http://www.securityfocus.com/bid/52689
http://www.openwall.com/lists/oss-security/2012/03/24/1
http://www.openwall.com/lists/oss-security/2012/03/22/9
http://secunia.com/advisories/48504
http://lists.wikimedia.org/pipermail/mediawiki-announce/2012-March/000110.html
http://lists.wikimedia.org/pipermail/mediawiki-announce/2012-March/000109.html