John Coltrane
Just one day after 2.7 RC 2 was released, the real deal, WordPress 2.7 “Coltrane” has hit the servers and is a major change in not only the admin panel, but a lot of core changes as well.
There have been plenty of updates concerning what updates have happened, and many times that number on the admin area changes. With all of these major changes, it is a wonder this isn’t considered version 3.0!
Just to detail how major this update really is, take a look at the name, Coltrane. John …

The same security fix provided to WordPress has also been added to WordPress MU. Version 2.6.5 takes care of the XSS security risk and is issued as an immediate upgrade because it fixes these holes.
The files changed in the latest update are as follows:

tags/2.6.5/wp-signup.php

tags/2.6.5/wp-login.php

tags/2.6.5/wp-includes/post.php

tags/2.6.5/wp-includes/version.php

tags/2.6.5/wp-includes/wpmu-functions.php

tags/2.6.5/wp-includes/feed.php

tags/2.6.5/wp-includes/widgets.php

tags/2.6.5/wp-includes/rss.php

tags/2.6.5/xmlrpc.php

tags/2.6.5/wp-settings.php

tags/2.6.5/wp-admin/users.php

The latest version of WordPress MU can be downloaded here.

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