The lastest WordPress version 2.8.6, is now released. WordPress 2.8.6 fixes two security problems that have been found. The security fixes to WordPress 2.8.6 concerned registered, logged-in users who have posting privileges. So, needless to say, if you have untrusted authors on your blog, then upgrading to 2.8.6 is highly recommended.

You can download the lastest WordPress version 2.8.6 here, or if you have any WordPress 2.7+ version, you can upgrade directly from within your admin panel.