Description

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

Proof of Concept

When logging in, the login page 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.

If a username exists but the password is incorrect, the returned error will be "Incorrect password [403]".

If a username doesn't exist, the returned error will be "User not found [403]".

Impact

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