The Booking Calendar plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 10.14.10 via the `WPBC_FLEXTIMELINE_NAV` AJAX action. This is due to the nonce verification being conditionally disabled by default (`booking_is_nonce_at_front_end` option is `'Off'` by default). When the `booking_is_show_popover_in_timeline_front_end` option is enabled (which is the default in demo installations and can be enabled by administrators), it is possible for