CVE-2026-27855

CVSS 6.8 MEDIUMEPSS 0.3%CWE-294

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.8EPSS 0.3%KEV nãoPoC —Patch referenciado

Lifecycle

Mar 27, 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

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

Affected products

Open-Xchange GmbH · OX Dovecot Pro

Want to know if your infrastructure is exposed to this?

Talk to TrueHacking →

References

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