CVE-2026-24031: Dovecot

High severity, CVSS 8.2. EPSS: 0.4% chance of exploitation in the next 30 days.

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 version. No publicly available exploits are known.

Affected products

• Dovecot Dovecot: before 2.4.3 (fixed in 2.4.3)
• Open-Xchange Dovecot: before 3.1.4 (fixed in 3.1.4)

Published 2026-03-27. Last modified 2026-07-15.