The REST API endpoint getusers in the User Profile Picture WordPress plugin before 2.5.0 returned more information than was required for its functionality to users with the uploadfiles capability. This included password hashes, hashed user activation keys, usernames, emails, and other less sensitive information.

The User Profile Picture plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.6.1 via the 'restapichangeprofileimage' function due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Author-level access and above, to update the profile picture of any user.