Out-of-bounds Write Affecting dovecot package, versions [2.3.0,2.4.5)
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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- published24 Sept 2026
- disclosed28 Aug 2026
- creditUnknown
Introduced: 28 Aug 2026
CVE-2026-40013 (opens in a new tab)How to fix?
Upgrade dovecot to version 2.4.5 or higher.
Overview
Affected versions of this package are vulnerable to Out-of-bounds Write in the ManageSieve process when compiling a Sieve script containing an extreme numeric literal. An attacker can cause memory corruption and crash the process by submitting a specially crafted script after authenticating.
Workaround
This vulnerability can be mitigated by disabling the ManageSieve service if remote Sieve script management is not required. Remove sieve from the protocols setting in the Dovecot configuration and restart the service.