Traveler <= 3.1.6 - Missing Authorization in Several AJAX Actions

The Travel Booking WordPress Theme theme for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the '__stPartnerCreateServiceRental', 'st_delete_order_item', '_st_partner_approve_booking', 'save_order_item', and '__userDenyEachInfo' functions in all versions up to, and including, 3.1.6. This makes it possible for authenticated attackers, with Subscriber-level access and above, to modify posts, delete posts and pages, approve arbitrary orders, insert orders with arbitrary prices, and deny user information.