According to Lorelle VanFossen WordPress 2.7 will be released within days:

An update to WordPress was released today. It is a security fix and is recommended for all users. According to Peter Westwood, the update contains one security fix and some bug fixes. 
I have compiled a list of the files that were changed. These can be captured from WordPress Trac. 

tags/2.6.5/wp-includes/post.php
tags/2.6.5/wp-includes/version.php
tags/2.6.5/wp-includes/feed.php
tags/2.6.5/xmlrpc.php
tags/2.6.5/wp-admin/users.php

Read about the update and download it from WordPress.org