CVE-2026-40205

Medium

Description

An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more than one scope is required in the configuration, the remote token validation paths accept a token that carries only one of them, while the local token validation path correctly requires all of them. The configured authorization policy is not enforced, so a token that was granted only part of the required permissions is accepted where it should have been rejected. Use local token validation where tokens can be validated locally. Update to non-vulnerable version. No publicly available exploits are known.

SeverityMedium
CVSS5.9
Exploit probability—
ProductOX Dovecot Pro
PublishedAug 28, 2026
First seenAug 28, 2026

How to fix

Update
  • Open-Xchange GmbH OX Dovecot Pro2.3.22.2, 3.0.7, 3.1.6 or later
  • Open-Xchange GmbH OX Dovecot CE2.4.5 or later

Affected products

ProductAffected versionsFixed in
Open-Xchange GmbH OX Dovecot Pro2.3.11.2 ≤ v < 2.3.22.2, 3.0.0 ≤ v < 3.0.7, 3.1.0 ≤ v < 3.1.62.3.22.2, 3.0.7, 3.1.6
Open-Xchange GmbH OX Dovecot CE2.3.11.2 ≤ v < 2.4.52.4.5

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