WordPress has announced the release of WordPress version 3.0.4 and has indicated that it is rated critical...
...is a very important update to apply to your sites as soon as possible because it fixes a core security bug in our HTML sanitation library, called KSES. I would rate this release as “critical.”
WordPress update information can be viewed at the below link.
Note that it is recommended that all sites that run WordPress (and any other third party script) subscribe to any security or announcement mailing list that may be provided by the Authors to stay up to date with new releases and security issues.
Information regarding the Mailing Lists available from WordPress may be viewed at this link.