Out-of-bounds Read in Open-Xchange Gmbh Ox Dovecot Ce
CVE-2026-40015
An attacker that has valid credentials can open many connections to the imap-hibernate service and send invalid commands, which can intermittently cause an out-of-bounds read and crash the process. The crash interrupts hibernated IMAP sessions handled by the affected process, which can cause degradation of service for IMAP. Disable IMAP hibernation. Update to non-vulnerable version. No publicly available exploits are known.
Vulnerability class: Buffer Overflow
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
Affected products
Weakness classification (CWE)
References
- security@open-xchange.com (vendor-advisory)
Frequently asked questions
- What is CVE-2026-40015?
- CVE-2026-40015 is a medium-severity vulnerability in Open-Xchange Gmbh Ox Dovecot Ce, classified under Out-of-bounds Read. CVSS score: 4.3/10. Published 2026-08-28.
- How severe is CVE-2026-40015?
- Medium severity. CVSS v3 base score is 4.3 out of 10.