WordPress 2.6.3 was released today to address a security risk in one of the included libraries WordPress uses. It is recommended for everybody to upgrade immediately. If you’re already using 2.6.2, the only 3 files you need to re-upload are:
- wp-includes/class-snoopy.php
- wp-includes/version.php
- wp-admin/includes/media.php
Which you can conveniently download in ZIP format right here.
If you’re not using 2.6.2, then you should re-upload all the files.
You should upgrade immediately to ensure your blog is protected from security risks.