# CVE-2025-59028: 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. - Web page: https://patchblox.com/security/cve/CVE-2025-59028 - Priority: High - CVSS: 7.5 (high) - EPSS: 0.0046 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 26, 2026 ## Description 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 | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dovecot Debian 13.5 (trixie) | 1:2.4.1+dfsg1-6+deb13u4 | [DEBIAN-CVE-2025-59028](https://patchblox.com/security/data/fix/linux/debian-cve-2025-59028.md) | Mar 27, 2026 | | Linux | dovecot Debian 14 | 1:2.4.3+dfsg1-1 | [DEBIAN-CVE-2025-59028](https://patchblox.com/security/data/fix/linux/debian-cve-2025-59028.md) | Mar 27, 2026 | | Linux | dovecot-auth-lua Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-auth-lua 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-auth-lua-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-core Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-core 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-core-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-flatcurve Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-flatcurve 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-flatcurve-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-gssapi Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-gssapi 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-gssapi-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-imapd Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-imapd 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-imapd-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-ldap Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-ldap 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-ldap-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-lmtpd Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-lmtpd 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-lmtpd-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-managesieved Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-managesieved 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-managesieved-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-mysql Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-mysql 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-mysql-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-pgsql Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-pgsql 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-pgsql-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-pop3d Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-pop3d 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-pop3d-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-sieve Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-sieve 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-sieve-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-solr Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-solr 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-solr-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-sqlite Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-sqlite 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-sqlite-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot-submissiond Ubuntu 25.10 (questing) | 1:2.4.1+dfsg1-5ubuntu4.1 | [dovecot-submissiond 1:2.4.1+dfsg1-5ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-dovecot-submissiond-1-2.4.1-dfsg1-5ubuntu4.1.md) | Apr 15, 2026 | | Linux | dovecot23 sles 15.6 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 | | Linux | dovecot23 sles 15.7 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 | | Linux | dovecot24 opensuse-leap 16.0 | 2.4.3-160000.1.1 | [OPENSUSE-SU-2026:20554-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20554-1.md) | Apr 16, 2026 | | Linux | dovecot24 sles 16.0 | 2.4.3-160000.1.1 | [SUSE-SU-2026:21208-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21208-1.md) | Apr 16, 2026 | --- Data as of 2026-11-09T07:25:28Z UTC. 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