CVEvulnerability

CVE-2026-27855

5.9 MEDIUM Published 2026-03-27 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-03-27
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.8 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 3.1 ([email protected])
5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weaknesses
CWE-294

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.

Affected configurations

• dovecot dovecot (< 2.4.3) • open-xchange dovecot (<= 2.3.0)

Related

Weakness · CWE (1)

  • CWE-294 Authentication Bypass by Capture-replay weakness

References