Risk: High
Numerous WordPress flaws have been found, some of which can facilitate Cross-Site Scripting and SQL injection. There are not only flaws in WordPress but also in the third party plugins which are available, one of which can result in Cross-Site Scripting if successfully exploited.
All flaws are detailed on a new site called Blog Security, which lists the flaws in order of which versions they have been found in:
http://blogsecurity.net/wordpress/blogwatch/blogwatch/
Users should be wary of downloading third party plugins that aren't actively supported and must always use the latest version when available. The most recent version of WordPress is 2.2; it's available to download at:
http://wordpress.org/download/