Microsoft says if you own a PC that runs windows, you need to update it immediately.
The Windows developer says the threat is from something called “print nightmare.”
It says researchers accidentally published a guide to exploiting it.
The company says hackers could use it to install programs, delete data and create new user accounts with full access to your machine.
In fact, the threat is so severe that the company issued a patch for the 12-year-old Windows 7 more than a year after ending support for it.
If you have automatic updates enabled, it’s likely your PC has already downloaded the security update.
Patches for operating systems aimed at IT professionals are expected soon.