A denial of service flaw was found in dovecot before 2.2.34. An attacker able to generate random SNI server names could exploit TLS SNI configuration lookups, leading to excessive memory usage and the process to restart.
The ssl-proxy-openssl.c function in Dovecot before 2.2.17, when SSLv3 is disabled, allow remote attackers to cause a denial of service (login process crash) via vectors related to handshake failures.
The auth component in Dovecot before 2.2.27, when auth-policy is configured, allows a remote attackers to cause a denial of service (crash) by aborting authentication without setting a username.
The IMAP functionality in Dovecot before 2.2.2 allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via invalid APPEND parameters.
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.
Dovecot 1.2.x before 1.2.15 allows remote authenticated users to cause a denial of service (master process outage) by simultaneously disconnecting many (1) IMAP or (2) POP3 sessions.
plugins/acl/acl-backend-vfile.c in Dovecot 1.2.x before 1.2.15 and 2.0.x before 2.0.5 interprets an ACL entry as a directive to add to the permissions granted by another ACL entry, instead of a directive to replace the permissions granted by another ACL entry, in certain circumstances involving the private namespace of a user, which allows remote authenticated users to bypass intended access restrictions via a request to read or modify a mailbox.