CVE-2026-33606: Open-Xchange GmbH Ox Dovecot CE

Medium severity, CVSS 4.8. EPSS: 0.2% chance of exploitation in the next 30 days.

Mail content stored by a user can be crafted so that it is interpreted as dsync protocol commands when an administrator later runs dsync with the stream protocol, for example during a migration. Injected commands can modify mailbox state on the destination during migration or replication, including internal mailbox attributes that a user should not be able to set directly. It can also cause dsync errors. Avoid running dsync with the stream protocol on mailboxes with untrusted content. Update to non-vulnerable version. No publicly available exploits are known.

Affected products

• Open-Xchange GmbH Ox Dovecot CE: from 2.3.0, before 2.4.5 (fixed in 2.4.5)
• Open-Xchange GmbH Ox Dovecot Pro: from 2.3.0, before 2.3.22.2 (fixed in 2.3.22.2); from 3.0.0, before 3.0.7 (fixed in 3.0.7); from 3.1.0, before 3.1.6 (fixed in 3.1.6)

Published 2026-08-28. Last modified 2026-09-03.