It may not be an actual update then. Virus and malware can cause it to say there is one when there isn't.
Try restarting the computer, but start up in "Safe Mode" and then check for updates. If it is a legit one, it will be listed in the updates area. If it isn't listed, then I would look into scanning the computer for viruses, malware, etc.
How to enter "Safe Mode" when booting the computer.
In Windows 8 and 10...
As your computer restarts, press F8 (possibly a few times) to enter "Safe Mode"
a. Press the "F4" key to Enable "Safe Mode".
(The computer will then start in "Safe Mode" with a minimal set of drivers and services.)
b. Press the "F5" key to Enable "Safe Mode" with Networking.
( Once "Safe Mode" with Networking starts...