Researchers with Google and their partners located an issue with computer processing chips that could allow hackers into almost any computer.
They're calling the flaws, "meltdown" and "Spectre," two different names for the two different ways hackers can gain access to computers where, once inside, they could steal personal information.
An attack on the computer chip could let a hacker capture sensitive information like passwords and encription keys.
A number of chip designs from Intel, ARM, and AMD are susceptible to the attacks.
The issue is windespread because the chips are used in devices made by Apple, Google, Amazon and others.
Microsoft sent an emergency patch they said should fix the problem, although it may slow down your computer.
Apple hasn't released anything after this announcement, but it's widely reported that some previous updates to their system already addressed the issue on many computers.
Experts suggest taking the security patches seriously.
Microsoft also said if you didn't receive a patch automatically, your antivirus software may have blocked it and you should contact your antivirus company to make sure the patch gets through.