WordPress 2.8.2 has been recently released by WordPress.org.
It fixes a XSS vulnerability in WordPress. The vulnerability would allow a hacker / cracker to add exploit code to the comments author url, as the comment author url’s were not fully sanitized when displaying in the admin. This could be exploited to forexample redirecting the admin to another site.
You can download the latest release of WordPress 2.8.2 from wordpress.org. Or install the upgrade directly from your wordpress admin through the tools > upgrade to 2.8.2
You can also check the upgrading from WordPress 2.8.1 to WordPress 2.8.2 in related articles.