WordPress
Security Update Issued
An update for WordPress was just released to address various security vulnerabilities and it is recommended that you update as soon as possible. Please login to the wp-admin of every WordPress installation of yours to perform the easy one-click update. If you are a reseller, please notify your clients of this very important security update as well to avoid having your website or accounts compromised.

Official Link:

https://wordpress.org/news/2014/11/wordpress-4-0-1/