MarketKing plugin for WordPress before 2.1.72 contains a missing authorization vulnerability in the marketking_admin_vendors_ajax AJAX action that allows authenticated attackers with subscriber-level access or higher to retrieve the complete vendor directory by sending a crafted AJAX request. Attackers can exploit the absence of capability checks in the vendor management action to retrieve internal user IDs, usernames, and email addresses of all registered vendors, exposing personally identifiable information to any logged-in user regardless of role.