In Sulu before versions 1.6.35, 2.0.10, and 2.1.1, when the "Forget password" feature on the login screen is used, Sulu asks the user for a username or email address. If the given string is not found, a response with a 400 error code is returned, along with a error message saying that this user name does not exist. This enables attackers to retrieve valid usernames. Also, the response of the "Forgot Password" request returns the email address to which the email was sent, if the operation was successful. This information should not be exposed, as it can be used to gather email addresses. This problem was fixed in versions 1.6.35, 2.0.10 and 2.1.1.