CVE-2026-27856 HIGH

CVE-2026-27856

Vendor Open-Xchange Gmbh
Product OX Dovecot Pro
Weakness CWE-287 · Improper authentication
Published March 27, 2026
Last update June 30, 2026

CVSS base score

7.4/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.

Key dates

02Disclosure timeline

March 27, 2026 CVE published
June 30, 2026 Record updated