CVE-2013-6171
checkpassword-reply in Dovecot before 2.2.7 performs setuid operations to a user who is authenticating, which allows local users to bypass authentication and access virtual email accounts by attaching to the process and using a restricted file descriptor to modify account information in the response to the dovecot-auth server.
Date published : 2013-12-09
http://wiki2.dovecot.org/AuthDatabase/CheckPassword#Security