Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a value sent by that host can be injected as an internal authentication field. Any host permitted to act as a trusted proxy can authenticate as any user without knowing that user's password. This affects deployments whose password database honours a field that permits authentication without a password. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.
History

Tue, 01 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Open-xchange
Open-xchange ox Dovecot Ce
Open-xchange ox Dovecot Pro
Vendors & Products Open-xchange
Open-xchange ox Dovecot Ce
Open-xchange ox Dovecot Pro

Tue, 01 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Title Trusted Proxy Authentication Bypass in OX Dovecot dovecot: Dovecot: Authentication bypass via trusted proxy forwarding
Weaknesses CWE-349
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 28 Aug 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 28 Aug 2026 14:00:00 +0000

Type Values Removed Values Added
Title Trusted Proxy Authentication Bypass in OX Dovecot

Fri, 28 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
Description Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a value sent by that host can be injected as an internal authentication field. Any host permitted to act as a trusted proxy can authenticate as any user without knowing that user's password. This affects deployments whose password database honours a field that permits authentication without a password. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.
Weaknesses CWE-287
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published: 2026-08-28T10:12:26.018Z

Updated: 2026-08-28T15:54:17.203Z

Reserved: 2026-04-23T11:15:21.199Z

Link: CVE-2026-42008

cve-icon Vulnrichment

Updated: 2026-08-28T14:32:35.986Z

cve-icon NVD

Status : Received

Published: 2026-08-28T12:16:29.380

Modified: 2026-08-28T20:17:30.170

Link: CVE-2026-42008

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-28T10:12:26Z

Links: CVE-2026-42008 - Bugzilla