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5.3 Medium

CVE-2026-40016 Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time…

Description

Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. No publicly available exploits are known.

Affected products and versions

Product Affected versions Fixed in
OX Dovecot Pro 2.3 earliest → 2.3.0 No fix stated

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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