The LearnPress – WordPress LMS Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 4.2.6.3 due to missing validation on a user controlled key when looking up order information. This makes it possible for authenticated attackers to obtain information on orders placed by other users and guests, which can be leveraged to sign up for paid courses that were purchased by guests. Emails of other users are also exposed.
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.