CVE-2026-40016
Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits
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.
MEDIUM · CVSS 5.3
EPSS 0.00016
Monitor
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0
YARA rules0