CVE-2026-27855

MEDIUM

6.8

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.

CVE Details

CVSS v3.1 Score6.8

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack VectorNETWORK

ComplexityHIGH

Privileges RequiredNONE

User InteractionREQUIRED

Published3/27/2026

Last Modified3/30/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-294

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json(security@open-xchange.com)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.