Improper Validation of Syntactic Correctness of Input 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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Test your applications- Snyk IDSNYK-UNMANAGED-DOVECOT-20078958
- published24 Sept 2026
- disclosed28 Aug 2026
- creditUnknown
Introduced: 28 Aug 2026
CVE-2026-33605 (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 Improper Validation of Syntactic Correctness of Input via the managesieve-login process. An attacker can cause the termination of all connections handled by the same process by sending a small malformed command before authentication, resulting in service disruption for Sieve script management. This is only exploitable if the service is running in high-performance mode, where multiple connections are handled by the same process.
Workaround
This vulnerability can be mitigated by restricting network access to the ManageSieve service to trusted clients only, such as by configuring a firewall to limit incoming connections to the service's port from specific IP addresses or networks.