Improper Verification of Source of a Communication Channel 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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Test your applications- Snyk IDSNYK-UNMANAGED-DOVECOT-16771151
- published20 May 2026
- disclosed12 May 2026
- creditUnknown
Introduced: 12 May 2026
CVE-2026-33603 (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 Improper Verification of Source of a Communication Channel in the SCRAM authentication process due to improper TLS channel binding verification. An attacker can intercept and read sensitive information by performing a man-in-the-middle attack with a specially crafted base64 exchange.
Workaround
This vulnerability can be mitigated by restricting network access to the server and configuring firewalls to allow connections only from trusted networks and necessary client IP ranges.