Dovecot before 1.0.10, with certain configuration options including use of %variables, does not properly maintain the LDAP+auth cache, which might allow remote authenticated users to login as a different user who has the same password.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10458
https://issues.rpath.com/browse/RPL-2076
http://www.vupen.com/english/advisories/2008/0017
http://www.ubuntu.com/usn/usn-567-1
http://www.securityfocus.com/bid/27093
http://www.securityfocus.com/archive/1/485787/100/0/threaded
http://www.securityfocus.com/archive/1/485779/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2008-0297.html
http://www.debian.org/security/2008/dsa-1457
http://secunia.com/advisories/32151
http://secunia.com/advisories/30342
http://secunia.com/advisories/28434
http://secunia.com/advisories/28404
http://secunia.com/advisories/28271
http://secunia.com/advisories/28227
http://lists.opensuse.org/opensuse-security-announce/2008-10/msg00004.html
http://dovecot.org/list/dovecot-news/2007-December/000058.html
http://dovecot.org/list/dovecot-news/2007-December/000057.html