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.

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Fixes

Solution

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Workaround

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History

Fri, 28 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published:

Updated: 2026-08-28T10:30:35.059Z

Reserved: 2026-03-23T12:58:38.267Z

Link: CVE-2026-33605

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T12:16:27.740

Modified: 2026-08-28T12:16:27.740

Link: CVE-2026-33605

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses