SecuriTricks - CVE-2026-27855

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.

Product(s) Impacted

Vendor	Product	Versions
Dovecot	Dovecot	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-294

Authentication Bypass by Capture-replay

A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	dovecot	dovecot	/	/	/	/	/	/	/	/

References

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

CVSS Score

6.8 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: HIGH
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: NONE

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

View Vector String

Timeline

Published: March 27, 2026, 9:16 a.m.
Last Modified: March 27, 2026, 9:16 a.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-27855