Affected: Open-Xchange GmbH OX Dovecot Pro

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 disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Affected: Ubuntu:22.04:LTS: dovecot, Ubuntu:24.04:LTS: dovecot, Ubuntu:25.10: dovecot

It was discovered that Dovecot incorrectly handled invalid base64 SASL data. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-59028)

It was discovered that Dovecot script decode2text.sh incorrectly handled zip files. An attacker could possibly use this issue to obtain sensitive information. (CVE-2025-59031)

It was discovered that Dovecot incorrectly handled certain AUTHENTICATE requests. An attacker could possibly use this issue to cause a denial of service. (CVE-2025-59032)

It was discovered that Dovecot incorrectly handled certain SQL based authentication. An attacker could possibly use this issue to bypass authentication. This issue only affected Ubuntu 25.10. (CVE-2026-24031)

It was discovered that Dovecot incorrectly handled certain LDAP based authentication. An attacker could possibly use this issue to bypass restrictions and allow probing of LDAP structure. This issue only affected Ubuntu 25.10. (CVE-2026-27860)

It was discovered that Dovecot is vulnerable to replay attack under certain conditions. An attacker could possibly use this issue to bypass authentication. (CVE-2026-27855)

It was discovered that Dovecot is vulnerable to a timing attack under certain conditions. An attacker could possibly use this issue to bypass authentication. (CVE-2026-27856)

It was discovered that Dovecot incorrectly handled certain IMAP login requests. An attacker could possibly use this issue to cause a denial…