If patching Windows servers and clients wasn't enough for you this month, there's also an update available to patch your WSUS servers.
Update KB2938066 is being released to harden WSUS's infrastructure files used by the WU/MU client and better secure the communication channel between the client and the server. When the update is applied to the WSUS server, the client will automatically be updated on WSUS-managed computers. If you opt to update the clients manually, the downloads are available HERE.
The update applies to WSUS 3.0 SP2, as well as the WSUS role running on Windows Server 2012 and Windows Server 2012 R2.
The WSUS 3.0 SP2 server will need to be updated manually, using this link: Update for Windows Server Update Services 3.0 SP2 (KB2938066)
Windows Server 2012 R2 and Windows Server 2012 can be updated over Windows Update, but I know many of you prohibit patches being applied to servers without your knowledge. The update for Windows Server 2012 R2 and Windows Server 2012 that fixes WSUS is included in this month's patches, so you can just deploy as you normally do using your management apparatus.
The specific patch that provides the WSUS update for Windows Server 2012 and Windows Server 2012 R2 is also listed as KB2938066, but there's a specific version for each version of Windows Server 2012.
Here's the direct download pages for each:
If you use System Center Configuration Manager, Microsoft has provided guidance on how to update clients with this newly released update: How to Install the Windows Update Agent on Client Computers