CVE-2026-66651

Subscriber Cross Site Scripting (XSS) in MultiVendorX <= 5.0.20 versions.

The MultiVendorX WordPress plugin before 5.0.16 does not verify that a user owns the store they are acting on in one of its REST API routes, allowing any authenticated user, such as a subscriber, to overwrite any store's details and payout settings and to replace the record of who owns it.

The MultiVendorX WordPress plugin before 5.0.16 does not restrict who can update its role and capability settings, allowing users holding its vendor role to grant that role administrator-level capabilities and take over the site.

Unauthenticated Broken Access Control vulnerability in MultiVendorX versions up to 5.0.10.

The MultiVendorX WordPress plugin before 5.0.11 does not verify that the requested store belongs to the current user in one of its REST API endpoints, allowing any vendor-level user to read other vendors' commission and financial data.

The MultiVendorX WordPress plugin before 5.0.11 does not verify that the store targeted through its REST API belongs to the requesting vendor, allowing an authenticated vendor (Store Owner and above) to view, take over, permanently delete, or modify any other vendor's store on the marketplace.

The MultiVendorX plugin for WordPress is vulnerable to generic SQL injection via the 'order_by' parameter in versions up to and including 5.0.9. Insufficient escaping and lack of proper SQL query preparation allow authenticated attackers with subscriber-level access or higher to append additional SQL queries.