Ive upgraded my wordpress installation to 2.6.3 tonight.
A vulnerability in the Snoopy library was announced today. WordPress uses Snoopy to fetch the feeds shown in the Dashboard. Although this seems to be a low risk vulnerability for WordPress users, we wanted to get an update out immediately. 2.6.3 is available for download right now.
More info at http://wordpress.org/development/2008/10/wordpress-263/