Vulnerability · Published Aug 28, 2026 · Assigned by OX
CVE-2026-52681
Low 3.1
In plain English
A low-severity security flaw 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 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | dovecot | 2.4.5-r0 | ALPINE-CVE-2026-52681 |
| Alpine:v3.24 | dovecot | 2.4.5-r0 | ALPINE-CVE-2026-52681 |
| Debian:12 | dovecot | 1:2.3.19.1+dfsg1-2.1+deb12u7 | DEBIAN-CVE-2026-52681 |
| Debian:13 | dovecot | 1:2.4.1+dfsg1-6+deb13u7 | DEBIAN-CVE-2026-52681 |
| Debian:14 | dovecot | 1:2.4.5+dfsg1-1 | DEBIAN-CVE-2026-52681 |
| Ubuntu:22.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-52681 |
| Ubuntu:24.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-52681 |
| Ubuntu:26.04:LTS | dovecot | no fix listed | UBUNTU-CVE-2026-52681 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Open-Xchange GmbH | OX Dovecot Pro | 2.3.15 – before 2.3.22.23.0.0 – before 3.0.73.1.0 – before 3.1.6 |
| Open-Xchange GmbH | OX Dovecot CE | 2.3.15 – before 2.4.5 |
Weakness: CWE-1050 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L