Medium severity · published Aug 28, 2026
CVE-2026-40205
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…
5.9
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OD
OX Dovecot CE · Open-Xchange GmbH
2.3.11.2 before 2.4.5 · source: vendor
OD
OX Dovecot Pro · Open-Xchange GmbH
2.3.11.2 before 2.3.22.2; 3.0.0 before 3.0.7; 3.1.0 before 3.1.6 · source: vendor
Affected product
OD
OX Dovecot CE
Open-Xchange GmbH
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