CVE-2026-27855
Dovecot vulnerability analysis and mitigation

Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.


SourceNVD

Related Dovecot vulnerabilities:

CVE ID

Severity

Score

Technologies

Component name

CISA KEV exploit

Has fix

Published date

CVE-2026-27858HIGH7.5
  • DovecotDovecot
  • dovecot-pgsql-debuginfo
NoYesMar 27, 2026
CVE-2026-27856HIGH7.4
  • DovecotDovecot
  • dovecot-debuginfo
NoYesMar 27, 2026
CVE-2026-27859MEDIUM5.3
  • DovecotDovecot
  • dovecot-pgsql
NoYesMar 27, 2026
CVE-2026-27857MEDIUM4.3
  • DovecotDovecot
  • dovecot-debugsource
NoYesMar 27, 2026
CVE-2026-27860LOW3.7
  • DovecotDovecot
  • dovecot-devel
NoYesMar 27, 2026

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