Vulnerability · Published Aug 28, 2026 · Assigned by OX
CVE-2026-42393
Low 3.1
In plain English
A low-severity information exposure in OX Dovecot CE from Open-Xchange GmbH. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | dovecot | 2.4.5-r0 | ALPINE-CVE-2026-42393 |
| Alpine:v3.24 | dovecot | 2.4.5-r0 | ALPINE-CVE-2026-42393 |
| Debian:12 | dovecot | 1:2.3.19.1+dfsg1-2.1+deb12u7 | DEBIAN-CVE-2026-42393 |
| Debian:13 | dovecot | 1:2.4.1+dfsg1-6+deb13u7 | DEBIAN-CVE-2026-42393 |
| Debian:14 | dovecot | 1:2.4.5+dfsg1-1 | DEBIAN-CVE-2026-42393 |
| Ubuntu:22.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-42393 |
| Ubuntu:24.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-42393 |
| Ubuntu:26.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-42393 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Open-Xchange GmbH | OX Dovecot Pro | 2.3.0 – before 2.3.22.23.0.0 – before 3.0.73.1.0 – before 3.1.6 |
| Open-Xchange GmbH | OX Dovecot CE | 2.3.0 – before 2.4.5 |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N