This module introduces an OAuth 2.0 authorization server, which can be configured to protect your Drupal instance with access tokens, or allow clients to request new access tokens and refresh them.
The module doesn't sufficiently respect granted scopes, it affects all access checks that are based on roles. For example: routes that have the _role requirement, can be bypassed with an access token.
This vulnerability is mitigated by the fact that an attacker must have the access token in possession and the user related to the token must have the associated (role requirement) roles assigned.
Update: the Affected versions field was updated to reflect that this vulnerability was present in the 6.0.0 release and fixed in 6.0.7. Earlier versions of this advisory incorrectly stated that other versions were affected.