According to the researchers, the Meltdown flaw affects virtually every microprocessor made by Intel, which makes chips used in more than 90 percent of the computer servers that underpin the internet and private business operations.

Customers of Microsoft, the maker of the Windows operating system, will need to install an update from the company to fix the problem. The worldwide community of coders that oversees the open-source Linux operating system, which runs about 30 percent of computer servers worldwide, has already posted a patch for that operating system. Apple had a partial fix for the problem and is expected to have an additional update.

The software patches could slow the performance of affected machines by 20 to 30 percent, said Andres Freund, an independent software developer who has tested the new Linux code. The researchers who discovered the flaws voiced similar concerns.

This could become a significant issue for any business running websites and other software through cloud systems.

There is no evidence that hackers have taken advantage of the vulnerability — at least not yet. But once a security problem becomes public, computer users take a big risk if they do not install a patch to fix the issue. A so-called ransomware attack that hit computers around the world last year took advantage of machines that had not received a patch for a flaw in Windows software.

The other flaw, Spectre, affects most processors now in use, though the researchers believe this flaw is more difficult to exploit. There is no known fix for it, and it is not clear what chip makers like Intel will do to address the problem.

It is not certain what the disclosure of the chip issues will do to Intel’s business, and on Wednesday, the Silicon Valley giant played down the problem.