WordPress 2.8.6 Released
In case you didn’t notice the message on top of your WordPress dashboard, WordPress 2.8.6 is now available. The release fixes two security problems that can be exploited by registered and logged in users with posting privileges.
Basically if you have untrusted users on your blog with a user level of “Author” or above, upgrading is highly recommended.
I’m sure you know the drill by now, make sure you backup before you upgrade. I haven’t heard of any upgrade issues with this release so it should be relatively painless.