Bug 2525590 (CVE-2026-40015)

Summary: CVE-2026-40015 dovecot: Dovecot: Denial of Service via malformed IMAP commands in imap-hibernate service
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Dovecot's imap-hibernate service. An authenticated attacker can open numerous connections and send malformed commands, leading to an out-of-bounds read. This can intermittently crash the process, interrupting hibernated IMAP sessions and causing a denial of service for affected users.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2526674    
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Description OSIDB Bzimport 2026-08-28 11:24:58 UTC 
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.