Description

The software generates an error message that includes sensitive information about its environment, users, or associated data.

Proof of Concept

1. The forgot password feature will tell you whether or not a username exists which is a vulnerability since it can be paired with the lack of rate limitation when logging in in order to help an attacker find out which accounts exist & then brute force those accounts' login credentials.
2. If a username exist and you click "Forgot your password?" the returned error will be "We have sent you an E-mail with instructions on how to reset your password. Please check your inbox.".
3. If a username do not exist and you click "Forgot your password?" the returned error will be "Sorry, but we could not find an account with the provided e-mail adress.".

Impact

Often this will either reveal sensitive information which may be used for a later attack or private information stored in the server.