Ninja Forms Missing Authorization in submissions-table Gutenberg Block Discloses Form Submissions to Unauthenticated Visitors

Ninja Forms WordPress plugin version 3.14.8 and prior contains a missing authorization vulnerability in the render callback of the ninja-forms/submissions-table Gutenberg block that allows authenticated attackers with Author-level privileges to expose stored form submissions to unauthenticated visitors by embedding the block with an arbitrary formID on a published post. Attackers can retrieve the signed bearer token injected into every page visitor's browser via wp_localize_script and use it against the REST API submissions endpoint to access all saved form submission field values, including sensitive personally identifiable information such as names, email addresses, and phone numbers.