VULNERABILITY INTELLIGENCE

CVE-2026-27855

CVSS score6.8 MEDIUM
EPSS probability0.32%
CISA KEVNot currently listed
Published2026-03-27
Last modified2026-10-26
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Description

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.

Weakness classification

  • security@open-xchange.com: CWE-294

Primary references