In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can fail for quoted strings. This occurs because '\0' characters are mishandled, and can lead to out-of-bounds writes and remote code execution.
The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate with an invalid UTF-8 sequence as the username.
In Dovecot before 2.2.36.3 and 2.3.x before 2.3.5.1, a local attacker can cause a buffer overflow in the indexer-worker process, which can be used to elevate to root. This occurs because of missing checks in the fts and pop3-uidl components.
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.
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.
Directory traversal vulnerability in the ManageSieve implementation in Dovecot 1.0.15, 1.1, and 1.2 allows remote attackers to read and modify arbitrary .sieve files via a ".." (dot dot) in a script name.
dovecot 1.0.7 in Red Hat Enterprise Linux (RHEL) 5, and possibly Fedora, uses world-readable permissions for dovecot.conf, which allows local users to obtain the ssl_key_password parameter value.