Developing a secure front end posting form

I want to add a front end posting functionality to one of my WordPress sites. For more control and for more understanding of how this works (I am not a professional programmer) I choosed to use as a base for future development a solution from the wpkb.com site (see the bellow code). This solution works, but the question is how it is protected against security issues/malicious attacks?

How to add “Stick this post to the front page” to front end?

I have a baseball related website with multiple authors. I use the “Stick this post to the front page” to denote an “Editor’s Pick” on an article. I would like to add a link/button to allow editor to do this from the front end. The method can either be in the article itself or in the Admin Bar. I do not really have a preference.