The vulnerability lies in the weak password policy for new user creation in NovoSGA. The analysis of the source code of the novosga/users-bundle which handles user management, reveals the root cause. The user creation process is handled by the DefaultController. The add method in this controller is the entry point for the /novosga.users/new path. This method, in turn, calls the private form method, which manages the form processing. The form itself is defined in UsuarioType. The buildForm method within UsuarioType sets the validation rules for the form fields. For the password field (senha), the only validation constraint is a minimum length of 6 characters (new Length([ 'min' => 6 ])). There are no constraints for character complexity (e.g., requiring uppercase, lowercase, numbers, or special characters). This allows for the creation of users with very weak passwords, such as '123456', as described in the vulnerability report. An attacker can exploit this by creating a user with a weak, easily guessable password and potentially gain unauthorized access.