CVE-2026-40020: Dovecot

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_allow_anyone=no. This causes folders to be spammed to all users. The impact is limited to being able to spam folders to other users, no unexpected access is gained. Install to fixed version. No publicly available exploits are known.

Affected products

• Dovecot Dovecot: before 2.4.4 (fixed in 2.4.4)
• Open-Xchange Dovecot: before 3.1.5 (fixed in 3.1.5)

Published 2026-05-12. Last modified 2026-06-17.