Stop User Enumeration plugin <1.3.9 - User Enumeration

The Stop User Enumeration plugin for WordPress is vulnerable to User Enumeration in versions up to, and including, 1.3.8. This is due to a flaw that was found in the REST API. This makes it possible for unauthenticated attackers to perform a POST request in the REST API allows simulating different request types. As such, attackers can perform a POST request with the “users” string in the body of the request, and tell the REST API to act like it’s received a GET request.