Event Booking Manager for WooCommerce <= 5.7.8 - Authenticated (Shop Manager+) Privilege Escalation to 'page' Parameter

The Mage Eventpress plugin for WordPress is vulnerable to privilege escalation in versions up to, and including, 5.7.8 This is due to the mep_grant_shop_manager_access() function hooking user_has_cap and unconditionally granting manage_options whenever an attacker-controllable request marker matches — most notably $_GET['page'] starting with 'mep_' or 'mpwem_', which is never validated against an actually registered EventPress screen. This makes it possible for authenticated attackers, with Shop Manager-level access and above, to elevate their privileges to Administrator by appending ?page=mep_x to core admin URLs (options-general.