doorkeeper-gem doorkeeper-openid_connect up to 1.10.3 Dynamic Client Registration Scope privileges management

Summaryinfo

A vulnerability classified as critical has been found in doorkeeper-gem doorkeeper-openid_connect up to 1.10.3. The affected element is the function DynamicClientRegistrationController#application_params of the component Dynamic Client Registration. This manipulation of the argument Scope causes privileges management. This vulnerability is handled as CVE-2026-70665. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in doorkeeper-gem doorkeeper-openid_connect up to 1.10.3 and classified as critical. Affected by this vulnerability is the function DynamicClientRegistrationController#application_params of the component Dynamic Client Registration. The manipulation of the argument scope with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Doorkeeper OpenID Connect implements an OpenID Connect authentication provider for Rails applications on top of Doorkeeper. Prior to 1.10.4, the Dynamic Client Registration (DCR) endpoint persists client-supplied scopes without validating them against the server's configured scope set. Under certain conditions, this allows a self-registered client to obtain scopes beyond what the server intended to grant. In DynamicClientRegistrationController#application_params, the scopes attribute is assigned directly from params[:scope] with no validation against Doorkeeper.configuration.scopes or optional_scopes. Combined with enforce_configured_scopes being off by default and Doorkeeper's ScopeChecker prioritizing application-level scopes over server-level scopes, this creates a privilege escalation path. This issue is fixed in version 1.10.4.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-70665 since 08/04/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 1.10.4 eliminates this vulnerability.

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Productinfo

Vendor

• doorkeeper-gem

Name

• doorkeeper-openid_connect

Version

• 1.10.0
• 1.10.1
• 1.10.2
• 1.10.3

Website

• Product: https://github.com/doorkeeper-gem/doorkeeper-openid_connect/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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