Vulnerabilities

When safe filter is used with variable expansion, all following pipelines on the same string are incorrectly interpreted as safe too, enabling unsafe data to be unescaped. This can enable SQL / LDAP injection attacks when used in authentication. Avoid using safe filter until on fixed version. No publicly available exploits are known.

Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability allows bypassing authentication for any user and user enumeration. Do not clear auth_username_chars. If this is not possible, install latest fixed version. No publicly available exploits are known.

An issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration entries exist with the same driver and args settings, incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation in certain configurations. The documentation does not advise against the use of passdb definitions that have the same driver and args settings. One such configuration would be where an administrator wishes to use the same PAM configuration or passwd file for both normal and master users but use the username_filter setting to restrict which of the users is able to be a master user.

Dovecot before 2.3.15 allows ../ Path Traversal. An attacker with access to the local filesystem can trick OAuth2 authentication into using an HS256 validation key from an attacker-controlled location. This occurs during use of local JWT validation with the posix fs driver.

Dovecot before 2.3.13 has Improper Input Validation in lda, lmtp, and imap, leading to an application crash via a crafted email message with certain choices for ten thousand MIME parts.

In Dovecot before 2.3.11.3, sending a specially formatted RPA request will crash the auth service because a length of zero is mishandled.

In Dovecot before 2.3.10.1, unauthenticated sending of malformed parameters to a NOOP command causes a NULL Pointer Dereference and crash in submission-login, submission, or lmtp.

lib-smtp in submission-login and lmtp in Dovecot 2.3.9 before 2.3.9.3 mishandles truncated UTF-8 data in command parameters, as demonstrated by the unauthenticated triggering of a submission-login infinite loop.

In Dovecot before 2.3.9.2, an attacker can crash a push-notification driver with a crafted email when push notifications are used, because of a NULL Pointer Dereference. The email must use a group address as either the sender or the recipient.

A postinstall script in the dovecot rpm allows local users to read the contents of newly created SSL/TLS key files.

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.

In the IMAP Server in Dovecot 2.3.3 through 2.3.5.2, the submission-login component crashes if AUTH PLAIN is attempted over a TLS secured channel with an unacceptable authentication message.

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.

It was discovered that Dovecot before versions 2.2.36.1 and 2.3.4.1 incorrectly handled client certificates. A remote attacker in possession of a valid certificate with an empty username field could possibly use this issue to impersonate other users.

Dovecot before version 2.2.29 is vulnerable to a denial of service. When 'dict' passdb and userdb were used for user authentication, the username sent by the IMAP/POP3 client was sent through var_expand() to perform %variable expansion. Sending specially crafted %variable fields could result in excessive memory usage causing the process to crash (and restart), or excessive CPU usage causing all authentications to hang.

A specially crafted email delivered over SMTP and passed on to Dovecot by MTA can trigger an out of bounds read resulting in potential sensitive information disclosure and denial of service. In order to trigger this vulnerability, an attacker needs to send a specially crafted email message to the server.

A flaw was found in dovecot 2.0 up to 2.2.33 and 2.3.0. An abort of SASL authentication results in a memory leak in dovecot's auth client used by login processes. The leak has impact in high performance configuration where same login processes are reused and can cause the process to crash due to memory exhaustion.

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.