This module introduces an OAuth 2.0 authorization server, which can be configured to protect your Drupal instance with access tokens, or allow clients...

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.

Since version 6.1.0, the module could cache a token's permissions in a way that let them be reused for another user's token with the same scopes. A user could gain permissions they do not have, including administrative access.

This vulnerability is mitigated by the fact that an attacker needs an OAuth2 token, and cannot trigger the issue themselves: a more privileged user's token with the same scopes must be used first. User 1 is not affected unless security.enable_super_user is set to false.