I have seen this yesterday, so to spread the word:
Regarding anyone running Windows 10 on their device:
The NSA has released an official, public statement urging everyone to update their Windows devices as soon as possible. An exploit has been identified in the current version of Windows 10 that can allow malicious software to be automatically installed on your computer, under the guise of approved Windows updates.
This means that very soon, hackers will be developing tools to be able to take control of and install malicious software to over 900 million PCs worldwide, with little to nothing that can be done to stop or remove the infected software due to the system believing it is from an approved Windows Update.
The NSA and US Department of Defense urges everyone on Widows 10 to update their computer IMMEDIATELY, as a fix for the exploit has already been released. Again, failing to update now will put your machine at extreme risk in the future.
To update, click the windows logo in the bottom left, click the cog, go to "update and security" and press "check for updates."
First Link, to the OFFICIAL NSA statement text document download (PDF), second link detailed news report :
Government agencies use off-the-shelf Windows-based PCs, so it's in their interest to see security flaws fixed. If they really want to track you, they don't need some mythical 'back door' into your computer. So, I'd say this one's likely on the level.