Cross-site request forgery (CSRF) vulnerability in the user options page in GNU Mailman 2.1.x before 2.1.23 allows remote attackers to hijack the authentication of arbitrary users for requests that modify an option, as demonstrated by gaining access to the credentials of a victim's account.
https://bugs.launchpad.net/bugs/1614841
http://www.securitytracker.com/id/1036728