The PeepSo Core: File Uploads plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 6.4.6.0 via the file_download REST API endpoint due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to download files uploaded by others users and expose potentially sensitive information.
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.