WordPress 2.6.5  has been released. This release fixes a security problem as well as 3 other minor fixes.
he security issue is an XSS exploit discovered by Jeremias Reith that fortunately only affects IP-based virtual servers running on Apache 2.x. If you are interested only in the security fix, copy wp-includes/feed.php and wp-includes/version.php from the 2.6.5 release package.
2.6.5 contains three other small fixes in addition to the XSS fix. The first prevents accidentally saving post meta information to a revision. The second prevents XML-RPC from fetching incorrect post types. The third adds some user ID sanitization during bulk delete requests. For a list of changed files, consult the full changeset between 2.6.3 and 2.6.5.
Note that we are skipping version 2.6.4 and jumping from 2.6.3 to 2.6.5 to avoid confusion with a fake 2.6.4 release that made the rounds. There is not and never will be a version 2.6.4.
5 files have been changed:
- /wp-admin/users.php 
- /wp-includes/feed.php 
- /wp-includes/post.php 
- /wp-includes/version.php 
- xmlrpc.php 
You can just download this 5 files and upload it to your server