This is a very simple Chrome extension that disables autoplay videos on the CNN website. If you'd like to read the reasoning behind it and how I made it, I documented that in a blog post.
I don't plan on adding this extension to the official Chrome Apps store, but feel free to download (or fork) for yourself and use it. And because this is primarily for my own use, I don't think I will accept any pull requests or fix any issues not reported by myself.