CVE-2026-73209 Denial of service in OX Dovecot CE
Authenticated attackers can crash the IMAP service by sending crafted compressed data, causing denial of service.
- 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-2026-73209?
CVE-2026-73209 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 send crafted compressed data that causes the affected process to exhaust its stack and crash. The affected process is terminated, which can cause degradation or denial of service for IMAP. Update to non-vulnerable version. No publicly available exploits are known.
Weakness: CWE-674
Which versions are affected by CVE-2026-73209?
How do I fix CVE-2026-73209?
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-2026-73209 being exploited?
There is no known exploitation of CVE-2026-73209 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-73209, AZL-98283, DEBIAN-CVE-2026-73209, GHSA-r5w4-jgmp-fp92, UBUNTU-CVE-2026-73209.