The WPshop 2 – E-Commerce plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions 2.0.0 to 2.6.0 via the callback_generate_api_key() due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Subscriber-level access and above, to create valid API keys on behalf of other users.
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.