Two major flaws in computer chips could leave a huge number of computers and smartphones vulnerable to security concerns, researchers revealed Wednesday.

The flaws could allow an attacker to read sensitive data stored in the memory, like passwords, or look at what tabs someone has open on their computer, researchers found. Daniel Gruss, a researcher from Graz University of Technology who helped identify the flaw, said it may be difficult to execute an attack, but billions of devices were impacted.

Called Meltdown and Spectre, the flaws exist in processors, a building block of computers that acts as the brain. Modern processors are designed to perform something called “speculative execution.” That means they predict what tasks they will be asked to execute and rapidly access multiple areas of memory at the same time.

That data is supposed to be protected and isolated, but researchers discovered that in some cases, the information can be exposed while the processor queues it up.

Researchers say almost every computing system – desktops, laptops, smartphones, and cloud servers – are affected by the Spectre bug. Meltdown appears to be specific to Intel (INTC) chips.

“More specifically, all modern processors capable of keeping many instructions in flight are potentially vulnerable. In particular, we have verified Spectre on Intel, AMD, and ARM processors,” the researchers said.

Government agencies issued statements warning users about the vulnerabilities.

The U.S. Computer Emergency Readiness Team said that while the flaws “could allow an attacker to obtain access to sensitive information,” it’s not so far aware of anyone doing so.

The agency urged people to read its detailed statement on the vulnerabilities, as well as those from Microsoft and Mozilla.

The U.K.’s National Cyber Security Center advised organisations and individuals to “continue to protect their systems from threats by installing patches as soon as they become available.”

Google (GOOGL) programmer Jann Horn of Project Zero was one of the researchers who discovered the flaws. In a blog post he said his group alerted chipmakers to the issues in June. Since last fall, security researchers and companies have investigated and updated software systems to address the bugs.

Intel chips are found in everything from personal computers to medical equipment. The company’s shares were down 3% on Wednesday.

The company said in a press release that “Many types of computing devices — with many different vendors’ processors and operating systems — are susceptible to these exploits.”

Intel said it is working with other chipmakers including AMD (AMD) and ARM Holdings to solve the issue. ARM said in a statement a small subset of its processors are susceptible to the flaws. AMD said in a statement there is a “near zero risk of exploitation” for one of the security issues, due to architecture differences.

A fix requires both the chip manufacturers and software makers to update their products before pushing it out.

Estimates posted on Linux message boards suggested computer performance could slow down between 5% and 30% once patched, however Intel said users will not see significant performance changes.

Tech website The Register was first to report the processor flaws on Tuesday.

A spokesperson for Microsoft (MSFT) told CNNMoney the company is aware of the issue and is in the process of deploying mitigations to cloud services and has released security updates to protect Windows users.

Google Cloud Platform has been updated to prevent the vulnerabilities, the company said.

Amazon (AMZN) said in a statement most of its cloud computing machines affected by the flaw are already protected, but it is updating the rest on Wednesday.

Researchers said patches were available for Apple’s (AAPL) OS X. The company did not respond to a request for comment.

It's important for all users to update their devices when new updates are released.

Flaws in chips are unusual. Back in 1994, a major error in Intel’s Pentium processor caused computers to incorrectly calculate results. (CNN)

Update news