dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation

A flaw was found in Dovecot. This vulnerability allows an attacker to bypass authentication by exploiting how OAuth2 tokens are validated. If an OAuth2 token response does not include a scope claim, Dovecot incorrectly uses the audience claim in its place for authorization checks. This can lead t...

Linux Distros Unpatched Vulnerability : CVE-2026-40205

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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...

CVE-2026-73208

An attacker that holds a token intended for a different purpose can authenticate, because when an OAuth2 token response does not contain a scope claim, the audience claim is used in its place and checked against the configured required scopes. These are different concepts, and the audience claim...

AZL-98307 CVE-2026-40205 affecting package dovecot 2.3.20-1

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...