Some sneaky hacker got into the Wordpress download server and placed a backdoor in the latest available version (2.1.1).
Luckily within a day someone reported the exploit to the Wordpress team and they took the site down to investigate.

This morning we received a note to our security mailing address about unusual and highly exploitable code in [...]

Recently a bug in certain versions of PHP came to the attention of the Wordpress developers, this bug could cause a security vulnerability in your any blogs running version 2.0.6 or below blog. It was fairly easy to work around, so they decided to release 2.0.7, just 10 days after the release of 2.0.6, to [...]

WordPress was “born out of a desire for an elegant, well-architectured personal publishing system built on PHP and MySQL and licensed under the GPL. It is the official successor of b2/cafelog. WordPress is fresh software, but its roots and development go back to 2001. It is a mature and stable product. We hope by focusing [...]

Yes that means all versions including the current version and before, 2.0.4 has not yet been released at the current time.
An exploit has been discovered in the current release of Wordpress, affecting Wordpress 2.0.3 and below (including 1.5.x) that allows these subscribed users to cause some serious damage.
It’s recommended at present if you are using [...]