If you use WordPress version 2.1.1, a dangerous security breach in that version has been discovered.
The announcement came late yesterday:
If you downloaded WordPress 2.1.1 within the past 3-4 days, your files may include a security exploit that was added by a cracker, and you should upgrade all of your files to 2.1.2 immediately.
[...] No downloads were altered except 2.1.1, so if you’ve downloaded any version of 2.0 you should be fine.
Please spread the word to anyone you know using WordPress version 2.1.1.