Nearly all computers worldwide - and many other devices - have been exposed to security flaws which leave them vulnerable to attacks by hackers
Researchers discovered gaps in security stemming from central processing units - better known as the chip or microchip - which could allow privately stored data in computers and networks to be hacked.
So far no data breaches have been reported. So is it a big deal and what does it mean for you?
There are two separate security flaws, known as Meltdown and Spectre.
Meltdown affects laptops, desktop computers and internet servers with Intel chips.
Spectre potentially has a wider reach. It affects chips in smartphones, tablets and computers powered by Intel, ARM and AMD.
Bryan Ma, a senior analyst at technology consultancy IDC, says data centres and devices that connect to the cloud are also at risk.
First, let's not panic. The UK's National Cyber Security Centre (NCSC) said there was no evidence that the vulnerability had been exploited.
But now that it has been made public, there's concern the bugs are discoverable and may be taken advantage of.
Consider the figures for personal computers alone: there are 1.5 billion in use today (desktop and laptop combined) and around 90% are powered by Intel chips, IDC estimates. That means exposure to the Meltdown bug is potentially huge.
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What information is at risk?
The bugs allow hackers to potentially read information stored on a computer memory and steal information like passwords or credit card data.
Technology analyst Jake Saunders from ABI Research said it was not exactly clear what information might be at risk, but as the security gaps had been exposed "the question is whether other parties can discover and potentially exploit them".