Search: CVE-2026-40013

CVE-2026-40013 is a buffer underwrite vulnerability in Open-Xchange GmbH OX Dovecot Pro's ManageSieve service. An attacker with valid credentials can submit a Sieve script containing an extreme numeric literal that triggers an out-of-bounds write during script compilation. This leads to memory corruption and crashes the ManageSieve process, causing denial of service for script management. There are no known public exploits. Disabling the ManageSieve service if not needed and updating to a non-vulnerable version are recommended.