A critical security vulnerability has prompted a warning from the National Security Agency to Windows 10 users that they should make sure to update their PCs ASAP.

The flaw could potentially allow what is called ‘spoofing.’ Spoofing is when malicious software is able to change its digital signature to impersonate software coming from a legitimate source. This is much the same way that scammers can change how their phone number displays to trick you into thinking a call is coming from a legitimate source.

Microsoft has issued a patch for this vulnerability and it may have already installed. If not, expect to receive it in the next few days. Here’s how to check to see if you have it. Type updates in your search box and click on the results.

updates

Click Check for updates.

check-forupdates

This should install the most recent Microsoft patches on your PC.