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7.5 High

CVE-2026-33605 An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before…

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.

Affected products and versions

Product Affected versions Fixed in
OX Dovecot Pro 3.1 3.1.0 → < 3.1.6 3.1.6
OX Dovecot Pro 3.0 3.0.0 → < 3.0.7 3.0.7
OX Dovecot Pro 2.3 2.3.0 → < 2.3.22.2 2.3.22.2
OX Dovecot CE 2.3 2.3.0 → < 2.4.5 2.4.5

Other CVEs of OX Dovecot Pro

The 44 CVEs of OX Dovecot Pro →
CVE-2026-73209 An attacker that has valid credentials can send crafted compressed data that causes the affected process to exhaust… 6.5 Medium CVE-2026-73208 An attacker that holds a token intended for a different purpose can authenticate, because when an OAuth2 token… 7.4 High CVE-2026-52687 An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression… 6.5 Medium CVE-2026-52681 Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the… 3.1 Low
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