GemBooking < 1.7.1 - Staff+ Arbitrary Post Deletion and Site Settings Update via REST Context Check Bypass

The GemBooking WordPress plugin before 1.7.1 does not properly verify that a REST request is addressed to its own routes before temporarily granting staff users administrative capabilities, allowing users with the GemBooking WordPress plugin before 1.7.1's Staff role to delete arbitrary posts and update the site's settings.