dovecot: When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authent...
CVE-2025-59028 is fixed in 18 products on 1 platform, first by DEBIAN-CVE-2025-59028, released March 27, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| dovecot · Debian 13.5 (trixie) | 1:2.4.1+dfsg1-6+deb13u4 | DEBIAN-CVE-2025-59028 | Mar 27, 2026 |
| dovecot · Debian 14 | 1:2.4.3+dfsg1-1 | DEBIAN-CVE-2025-59028 | Mar 27, 2026 |
| dovecot-auth-lua · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-auth-lua 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-core · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-core 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-flatcurve · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-flatcurve 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-gssapi · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-gssapi 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-imapd · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-imapd 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-ldap · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-ldap 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-lmtpd · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-lmtpd 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-managesieved · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-managesieved 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-mysql · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-mysql 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-pgsql · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-pgsql 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-pop3d · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-pop3d 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-sieve · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-sieve 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-solr · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-solr 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-sqlite · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-sqlite 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot-submissiond · Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | dovecot-submissiond 1:2.4.1+dfsg1-5ubuntu4.1 | Apr 15, 2026 |
| dovecot23 · sles 15.6 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 | Sep 14, 2026 |
| dovecot23 · sles 15.7 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 | Sep 14, 2026 |
| dovecot24 · opensuse-leap 16.0 | 2.4.3-160000.1.1 | OPENSUSE-SU-2026:20554-1 | Apr 16, 2026 |
| dovecot24 · sles 16.0 | 2.4.3-160000.1.1 | SUSE-SU-2026:21208-1 | Apr 16, 2026 |
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