CVE-2026-52681 Denial of service in OX Dovecot CE
Authenticated attackers can bypass CPU limits and leave orphaned files, causing resource exhaustion and service degradation in Dovecot mail 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-2026-52681?
CVE-2026-52681 is a low-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
Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedly changing the active script. Compiled script files are also not removed when a script is deleted or renamed. The configured Sieve CPU limit can be bypassed, allowing sustained CPU consumption, and the leftover files increase disk consumption. Both can cause degradation of service for mail delivery. Monitor system for abnormal CPU usage and disk consumption. Update to non-vulnerable version. No publicly available exploits are known.
Weakness: CWE-1050
Which versions are affected by CVE-2026-52681?
How do I fix CVE-2026-52681?
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-2026-52681 being exploited?
There is no known exploitation of CVE-2026-52681 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-52681, AZL-98271, DEBIAN-CVE-2026-52681, GHSA-x4gp-83hc-j86g, UBUNTU-CVE-2026-52681.