The Eventin plugin for WordPress is vulnerable to privilege escalation via account takeover in all versions up to, and including, 4.0.34. This is due to the plugin not properly validating a user's identity or capability prior to updating their details like email in the 'Eventin\Speaker\Api\SpeakerController::update_item' function. This makes it possible for unauthenticated attackers with contributor-level and above permissions to change arbitrary user's email addresses, including administrators, and leverage that to reset the user's password and gain access to their account.