CVE-2026-40015: Out-of-bounds Read in Open-Xchange GmbH OX Dovecot Pro
Description
CVE-2026-40015 is a medium severity vulnerability in Open-Xchange GmbH's OX Dovecot Pro. It involves an out-of-bounds read triggered by an attacker with valid credentials who opens many connections to the imap-hibernate service and sends invalid commands. This can intermittently crash the process, disrupting hibernated IMAP sessions and causing service degradation. No public exploits are known. Mitigation includes disabling IMAP hibernation and updating to a non-vulnerable version.
CVSS v3.1
Score 4.3medium
Affected software
Open-Xchange GmbH
OX Dovecot Pro
Open-Xchange GmbH
OX Dovecot CE
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability allows an authenticated attacker to cause an out-of-bounds read in the imap-hibernate service of OX Dovecot Pro by opening multiple connections and sending invalid commands. The resulting crash interrupts hibernated IMAP sessions handled by the affected process, leading to potential degradation of IMAP service availability. The vulnerability affects specific versions of OX Dovecot Pro (2.3.0, 3.0.0, 3.1.0). No public exploits have been reported.
Potential Impact
The primary impact is a denial of service condition caused by process crashes, which interrupt hibernated IMAP sessions and degrade IMAP service availability. There is no impact on confidentiality or integrity according to the CVSS vector. The vulnerability requires valid credentials and does not involve user interaction.
Mitigation Recommendations
Disabling IMAP hibernation is recommended as a temporary mitigation. Users should update to a non-vulnerable version of OX Dovecot Pro once available. Since no official patch or remediation level is provided in the vendor advisory, check the vendor's resources for updates. No public exploits are known, so immediate exploitation risk is low.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- OX
- Date Reserved
- 2026-04-08T09:59:59.342Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a916f8aacd9273b49cf91ff
Added to database: 08/28/2026, 11:22:50 UTC
Last enriched: 09/10/2026, 02:53:08 UTC
Last updated: 10/13/2026, 06:48:16 UTC
Views: 29
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