laravel/laravel — pull request #1086 by gaker (2012-08-11 02:07:41+00:00)
Title: Changing CSRF failure error code to 403.

Previously, the error code returned in application/routes.php
on a forged request/CSRF failure returned a 500 error. A 500
indicates a fatal PHP error or a server error, not what is
actually happening.

A 403 error makes more sense in this situation.