There is a bug in popular computer software and if hackers are able to take advantage of it, they could use that bug to break into computer systems worldwide.
The problem was discovered in software known as Log4j.
It's a library that keeps track of error messages in computer programs, but Log4j has a security flaw.
One that could make it possible for hackers to take control of servers, and because the software is so widely used throughout the technology industry, attackers could go after its flaw in countless places.
This could affect some pretty big companies, Amazon Apple, Google, Linkedin, Tesla, Twitter.
The game Minecraft has already been affected.
Its owner is Microsoft and it's had to put a patch or fix in place to lock the hackers back out.
So now other technology companies and businesses are being told to figure out if they've been affected by the software flaw.
And if so, to quickly take the steps necessary to fix it.
What makes things more complicated is that computer engineers didn't know about it and therefore prepare for it until news broke late last week that hackers were using the flaw to break into networks.
And in the first 72 hours after the flaw became public, cybersecurity firm Check Point said 800,000 attempts were made to take advantage of it.
The timing wasn't good either.
Check Point and the technology website CNET, said with the holidays approaching, information technology specialists maybe taking time off.
That could make it harder for companies to move quickly to patch the flaw.
Before they started moving to do that, hundreds of millions of devices might have been vulnerable to the bug.
What can individual users do? Not much.
According to CNET, people could just make sure they update their devices, software and applications whenever they're prompted to do it.
But that's a security step that computer users are encouraged to take anyway.
Most of us are walking a tightrope when it comes to protecting ourselves from the hackers, living on the edge thinking oh I won't fall.
That's why it's so important to protect yourself.
Just like you do a safety check before you perform a big stunt, you need to do a security check on your computer to make sure you're running the latest version of your operating system.
And you also have to do a backup of your most important files just in case, but if all that security lets you down encrypt your files with or Bitlocker.
And to be on solid ground, always run anti-virus software.
I'm going to log to log, but you probably feel like you're going from log in to log in, password to password.
There are so many opportunities for the hackers to get their hands on those.
So you should use two-step sign in.
That way every time you have to answer your password, you also get a code sent to your phone.
So even if the hackers steal your password, they won't get their hands on your Smartphone.