Bug 2525576 (CVE-2026-33605)

Summary: CVE-2026-33605 dovecot: Dovecot: Denial of Service in ManageSieve login process
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in Dovecot. An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. This can lead to a denial of service for Sieve script management, affecting either the attacker's connection or all connections handled by the same process, depending on the security mode.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2526669    
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Description OSIDB Bzimport 2026-08-28 11:23:50 UTC 
An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. If running in high-security mode (default for community releases), only the attacker's own connection is terminated. If running in high-performance mode (default for Pro releases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause denial of service for Sieve script management. Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.