MoinMoin 1.2.1 and earlier allows remote attackers to gain privileges by creating a user with the same name as an existing group that has higher privileges.
https://exchange.xforce.ibmcloud.com/vulnerabilities/16465
http://www.securityfocus.com/bid/10568
http://www.gentoo.org/security/en/glsa/glsa-200407-09.xml
http://sourceforge.net/tracker/index.php?func=detail&aid=948103&group_id=8482&atid=108482