WordPress has released 2.8.5. It is a hardening release, taking some of the latest enhancments from the upcoming 2.9 release. Highlights of the 2.8.5 release according to the WordPress blog are:

The headline changes in this release are:

• A fix for the Trackback Denial-of-Service attack that is currently being seen.
• Removal of areas within the code where php code in variables was evaluated.
• Switched the file upload functionality to be whitelisted for all users including Admins.
• Retiring of the two importers of Tag data from old plugins.

More details are available on the WordPress blog. Do not forget to backup your WordPress database and files before upgrading, just in case something goes wrong with the upgrade. The easiest way to upgrade is to use the built in upgrade feature inside WordPress. If you cannot use that feature or just prefer to use FTP to upload the new files you can download the new WordPress release to upload.