CVE-2026-40013
Medium
Description
An attacker that has valid credentials can submit a Sieve script containing an extreme numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script. This causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for script management. This might be able to be used for remote code execution. Disable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version. No publicly available exploits are known.
SeverityMedium
CVSS4.3
Exploit probability—
ProductOX Dovecot Pro
PublishedAug 28, 2026
First seenAug 28, 2026
Weakness typeCWE-124CWE-124
How to fix
Update
- Open-Xchange GmbH OX Dovecot Pro2.3.22.2, 3.0.7, 3.1.6 or later
- Open-Xchange GmbH OX Dovecot CE2.4.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Open-Xchange GmbH OX Dovecot Pro | 2.3.0 ≤ v < 2.3.22.2, 3.0.0 ≤ v < 3.0.7, 3.1.0 ≤ v < 3.1.6 | 2.3.22.2, 3.0.7, 3.1.6 |
| Open-Xchange GmbH OX Dovecot CE | 2.3.0 ≤ v < 2.4.5 | 2.4.5 |
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