For people using WP to run their blogs:

It appears that the files for 2.1.1 have been hacked into and corrupted, all wordpress 2.1* users are advised to upgrade to 2.1.2 as soon as possible.

You can read more on the dev blog: WordPress 2.1.1 dangerous, Upgrade to 2.1.2.

Technorati Tags: Wordpress, Blog Software, Software, Hacking