CVE-2025-59028: When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active…
CVE-2025-59028 · Severity: medium · CVSS 5.3 · Published 2026-03-27
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.
No. Junglewise Threat Intelligence has no report of CVE-2025-59028 being exploited in the wild.
How severe is CVE-2025-59028?
Medium severity, with a CVSS score of 5.3, published 27 March 2026.
Which products and versions are affected?
Dovecot, Open-Xchange Dovecot. The advisory does not name versions.
Is there a fix for CVE-2025-59028?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2025-59028?
Check whether you run Dovecot or Open-Xchange Dovecot. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.