CVE-2026-9851: Authorization Bypass Through User-Controlled Key

The Booking Package plugin for WordPress is vulnerable to Privilege Escalation via Account Takeover in versions up to, and including, 1.7.16. This is due to a missing capability check on the 'updateUser' branch of the package_app_action AJAX endpoint, where the handler only validates a nonce and the dispatcher invokes Schedule::updateUser() with the $administrator argument hard-coded to 1, bypassing the only owner-restriction check inside that function and allowing the target user to be determined solely by attacker-supplied input passed directly to wp_update_user(). This makes it possible for authenticated attackers, with Editor-level access and above, to change the email address and password of any account, including Administrator accounts, resulting in a full site takeover.