CVE-2026-33607 Denial of service in OX Dovecot CE
Authenticated attackers can cause CPU exhaustion and denial of service via the IMAP LIST command in Dovecot servers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33607?
CVE-2026-33607 is a medium-severity denial of service vulnerability in Open-Xchange GmbH OX Dovecot CE, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An attacker that has valid credentials can use IMAP LIST command to consume CPU. This can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed version. No publicly available exploits are known.
Weakness: CWE-400
Which versions are affected by CVE-2026-33607?
How do I fix CVE-2026-33607?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33607 being exploited?
There is no known exploitation of CVE-2026-33607 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-33607, AZL-98316, DEBIAN-CVE-2026-33607, GHSA-55w3-v95w-x9w3, UBUNTU-CVE-2026-33607.