Section
4.3.5
General
The application should verify that there is no unexpected data in any part of the request, and that there is no required data missing from the request.
Django

Most form fields have a "required" argument. When True, the user will get an error if the field is not filled.

Natural Webagent

Consider checking *form for extra or conflicting parameters.

.NET

RequiredFieldValidator can be used to ensure a required field is present.