Allocation of Resources Without Limits or Throttling Affecting dovecot package, versions [,2.4.4)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published25 May 2026
- disclosed12 May 2026
- creditUnknown
Introduced: 12 May 2026
CVE-2026-40016 (opens in a new tab)How to fix?
Upgrade dovecot to version 2.4.4 or higher.
Overview
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the ManageSieve process. An attacker can cause excessive resource consumption and degrade server performance by uploading a specially crafted Sieve script that bypasses configured CPU time limits.
Workaround
This vulnerability can be mitigated by restricting access to the ManageSieve service to trusted users or networks, disabling the ManageSieve service if not essential, and ensuring local user access to Sieve script directories is appropriately controlled.