CVE-2026-42393 Information disclosure in OX Dovecot CE
An attacker on the same network can measure response timing to reveal the length of the doveadm secret, aiding brute-force attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42393?
CVE-2026-42393 is a low-severity vulnerability in Open-Xchange GmbH OX Dovecot CE, published on 28 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The comparison used for the doveadm password and API key is not fully timing safe and can reveal the length of the configured secret. An attacker with access to the same network as the doveadm service, able to make repeated requests and measure response timing accurately, can learn the length of the secret, which reduces the effort needed to guess it. The secret value itself is not disclosed. Restrict network access to the doveadm service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.
Weakness: CWE-200
Which versions are affected by CVE-2026-42393?
How do I fix CVE-2026-42393?
Upgrade to a fixed version.
Is CVE-2026-42393 being exploited?
There is no known exploitation of CVE-2026-42393 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-42393, AZL-98310, DEBIAN-CVE-2026-42393, GHSA-j4gv-hpmc-xf3m, UBUNTU-CVE-2026-42393.