Resolving a Remote Code Execution Exploit

Magento recently identified potential exploits that:

Enable an attacker to execute arbitrary code on your Magento server.
Create files with a .csv extension, create writable directories, and change the permission of existing files to world-writable (777).
The following table shows the patch you should get for your version of CE or EE. :

Here are some informations about the patch installation on official Magento website :

How to apply a patch on Magento Community Edition?
How to apply a patch on Magento Enterprise Edition?

And, to finish, the official post about the exploit, and the way to patch it