WordPressプラグイン「Eventin – Events Calendar, Tickets, Registration, Booking & WooCommerce」に不適切な権限管理の脆弱性（CVE-2026-75983）

The Eventin – Event Calendar, Tickets, Registration, Booking & WooCommerce plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 4.1.23. This is due to the `PermissionManager::manage_permissions()` function being registered as a callback on WordPress core's `map_meta_cap` filter and unconditionally returning the always-true `'exist'` primitive for every capability check whenever the evaluated user ID is 1, without scoping this behavior to plugin-specific capabilities. This makes it possible for authenticated attackers whose account is user ID 1, even subscribers, to pass every WordPress capability check, including `manage_options`, `edit_plugins`, `edit_themes`, `promote_users`, and `update_core`, thereby elevating their privileges to administrator-equivalent power and achieving full site takeover, including remote code execution via the plugin and theme editors. Exploitation is only impactful when user ID 1 has been deliberately demoted to a lower-privilege role as a common administrator-account hardening practice; on default installations where user ID 1 retains the administrator role, no incremental privilege gain occurs.