CVE-2026-27855 (GCVE-0-2026-27855)
Vulnerability from cvelistv5 – Published: 2026-03-27 08:10 – Updated: 2026-03-27 19:39
VLAI
EPSS
VEX
Summary
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.
Severity
6.8 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-27 19:39 UTC
CWE
- CWE-294 - Authentication Bypass by Capture-replay
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://documentation.open-xchange.com/dovecot/se… | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Open-Xchange GmbH | OX Dovecot Pro |
Affected:
0 , ≤ 2.3.0
(semver)
|
guessed |
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