CVE-2026-27855
MEDIUM EPSS 25.6%
Published Mar 27, 20263mo ago · Modified Jun 17, 20262w ago
5.9 CVSS 3.1
Published Mar 27, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity None
Availability None
Threat Intelligence
EPSS Exploit Probability
25.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-294
Affected Products 2
| Vendor | Product | Version | Range |
|---|---|---|---|
| dovecot | dovecot | * | <2.4.3 |
| open-xchange | dovecot | * | ≤2.3.0 |
References 1
- documentation.open-xchange.com https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.