User Private Files <= 2.1.0 - Insecure Direct Object Reference to Authenticated (Subscriber+) Private File Access

The User Private Files – WordPress File Sharing Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.1.0 via the 'dpk_upvf_update_doc' due to missing validation on the 'docid' user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to gain access to other user's private files.