I used to use Wordpress to post and edit articles, but it was too bloated and not extensible enough. Fortunately I found this PHP script, which was originally written by Dustin Minnich. I extended it with a password feature to enable the user to edit sensitive files. It's not really complex enough to license, but if you download it or modify it, consider leaving a comment so I will know what kinds of applications people are using it for.
Simple PHP File Editor with Password Protection