The first WordPress 2.3 security issue has been found. It is in regard to the blogroll function in WordPress and results in unlimited spam entries being injected into your blogroll. This vulnerability is already being exploited by spammers. An explanation and a fixed file can be found here until a new point release of WordPress is available. This issue apparently also affects older versions of WordPress as well as the newest version, so pretty much anyone using the blogroll on their site should immediately address this issue.