Dovecot 1.2.x before 1.2.8 sets 0777 permissions during creation of certain directories at installation time, which allows local users to access arbitrary user accounts by replacing the auth socket, related to the parent directories of the base_dir directory, and possibly the base_dir directory itself.
lists.opensuse.org/opensuse-security-announce/2010-01/msg00007.html
marc.info/?l=oss-security&m=125871729029145&w=2
marc.info/?l=oss-security&m=125881481222441&w=2
marc.info/?l=oss-security&m=125900267208712&w=2
marc.info/?l=oss-security&m=125900271508796&w=2
secunia.com/advisories/37443
www.dovecot.org/list/dovecot-news/2009-November/000143.html
www.mandriva.com/security/advisories?name=MDVSA-2009:306
www.osvdb.org/60316
www.securityfocus.com/bid/37084
www.vupen.com/english/advisories/2009/3306
exchange.xforce.ibmcloud.com/vulnerabilities/54363