I'm not sure about 5.3.4 final, but it is written that some 5.3.4-snapshot versions also were affected.
NET MVC, controllers define action methods that usually have a one-to-one relationship with possible user interactions, such as clicking a link or submitting a form.
You can use data validation to restrict the type of data or the values that users enter into a cell.
One of the most common data validation uses is to create a drop-down list.
You can use the action filter attribute to mark any action method or controller.