Dovecot 1.1 before 2.2.13 and dovecot-ee before 2.1.7.7 and 2.2.x before 2.2.12.12 does not properly close old connections, which allows remote attackers to cause a denial of service (resource consumption) via an incomplete SSL/TLS handshake for an IMAP/POP3 connection.

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.

lib-mail/message-header-parser.c in Dovecot 1.2.x before 1.2.17 and 2.0.x before 2.0.13 does not properly handle '\0' characters in header names, which allows remote attackers to cause a denial of service (daemon crash or mailbox corruption) via a crafted e-mail message.

Dovecot 1.2.x before 1.2.15 and 2.0.x before 2.0.beta2 grants the admin permission to the owner of each mailbox in a non-public namespace, which might allow remote authenticated users to bypass intended access restrictions by changing the ACL of a mailbox, as demonstrated by a symlinked shared mailbox.