The E-cab Taxi Booking Manager for Woocommerce WordPress plugin before 2.0.5 does not validate a client-supplied trip distance and base-price value on the server before pricing a booking, allowing unauthenticated attackers to manipulate the order total down to zero and place real taxi-booking orders at an arbitrary price.
https://wpscan.com/vulnerability/241a7890-81b3-4685-a243-e774d560f17a/