Replay Attack Affecting dovecot package, versions [,2.4.3)
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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- published31 Mar 2026
- disclosed27 Mar 2026
- creditUnknown
Introduced: 27 Mar 2026
CVE-2026-27855 (opens in a new tab)How to fix?
Upgrade dovecot to version 2.4.3 or higher.
Overview
Affected versions of this package are vulnerable to Replay Attack via the OTP authentication process when the authentication cache is enabled and the username is altered in the password database. An attacker can gain unauthorized access by replaying a previously observed OTP exchange. This is only exploitable if both the authentication cache is enabled and the username is changed in the password database.
Workaround
This vulnerability can be mitigated by switching to the SCRAM protocol or ensuring communications are secured, and if possible, switching to OAUTH2 or SCRAM.