WordPress 2.8.1

Not even a month, the WordPress 2.8.1 is released on July 9, 2009 and it fixes many bugs and tightens security for plugin administration pages. It is advisable to upgrade to 2.8.1 as the admin pages added by certain plugins could be viewed by unprivileged users, resulting in information being leaked but not all plugins are vulnerable to this problem.

Nevertheless, you can view all changes since 2.8 to understand fixes. So, do upgrade your WordPress to WordPress 2.8.1 to avoid any information leaked out.

Source: WordPress