CVE-2026-27855
MEDIUM
MEDIUM
Priority: 0.02
BB Relevance:
62/100
Published: 2026-03-27
Modified: 2026-10-26
First seen: 2026-10-29
Status: active
Attack Surface
Network
No Auth
No Interaction
Conf. Impact
CVSS Vector Breakdown
AV:
Network
AC:
High
PR:
None
UI:
None
S:
Unchanged
C:
High
I:
None
A:
None
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 (1)
Affected Software (2)
| Vendor | Product | Version |
|---|---|---|
| dovecot | dovecot | < 2.4.3 |
| open-xchange | dovecot | < 2.3.0 |
References & Advisories (1)
Vendor Advisory