script-login in Dovecot 2.0.x before 2.0.13 does not follow the user and group configuration settings, which might allow remote authenticated users to bypass intended access restrictions by leveraging a script.
https://exchange.xforce.ibmcloud.com/vulnerabilities/67675
http://www.securityfocus.com/bid/48003
http://www.dovecot.org/doc/NEWS-2.0
http://secunia.com/advisories/52311
http://rhn.redhat.com/errata/RHSA-2013-0520.html