WordPress have released the security update today evening (by Ryan Boren). I haven’t get any update notification‚ inside Dashboard, till now. Its a Security Release, related to Privilege escalation exploit and highly recommended to update it immediately.
If you run a blog then navigate to Tools -> Upgrade option in your Dashboard, and you will find the option to upgrade.
You may also go for manual upgrade if necessary. And remember to back up your Files and Database before try updating the wordpress. Here the link to the Developer Site.