https://www.theverge.com/2018/1/4/16848976/how-to-protect-windows-pc-meltdown-security-flaw

Details have emerged on two major processor security flaws this week, and the industry is scrambling to issue fixes and secure machines for customers. Dubbed “Meltdown” and “Spectre,” the flaws affect nearly every device made in the past 20 years. The Meltdown flaw only affects Intel processors, and researchers have already released proof of concept code that could lead to attacks using Meltdown.

The vulnerabilities allow an attacker to compromise the privileged memory of a processor by exploiting the way processes run in parallel. They also allow an attacker to use JavaScript code running in a browser to access memory in the attacker’s process. That memory content could contain key strokes, passwords, and other valuable information. Researchers are already showing how easy this attack works on Linux machines, but Microsoft says it has “not received any information to indicate that these vulnerabilities have been used to attack customers at this time.”