Dovecot vulnerabilities
We track 7 vulnerabilities in Dovecot products. 7 are rated high or critical, and none are known to be exploited. The most recent was published on May 12, 2026.
Latest Dovecot vulnerabilities
- 9.1 Critical severity
OX Dovecot Pro: Improper Handling of Extra Parameters
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 sa
- 7.5 High severity
OX Dovecot Pro: Uncontrolled Resource Consumption
Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol
- 7.5 High severity
OX Dovecot Pro: Uncontrolled Resource Consumption
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker
- 8.2 High severity
OX Dovecot Pro: Improper Neutralization of Special Elements used in an SQL Command
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
- 7.5 High severity
ManageSieve AUTHENTICATE command crashes when using literal as SASL initial response.
ManageSieve AUTHENTICATE command crashes when using literal as SASL initial response. This can be used to crash ManageSieve service repeatedly, making it unavailable for other users. Control access to ManageSieve port, or disable the service if it's not needed
- 7.5 High severity
When sending invalid base64 SASL data, login process is disconnected from the auth server…
When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disab
- 8.8 High severity
Dovecot: Improper Authentication
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