Meltdown and Spectre are bugs that affect practically every computer and device that is out in the market. This Bugs at a fundamental level that allow critical information stored deep inside computer systems to be exposed. It’s not a physical problem with the CPUs themselves, or a plain software bug you might find in an application like Microsoft or linux or firefox or google Chrome. It’s at the level of the processors’ “architectures,” the way all the millions of transistors and logic units work together to carry out instructions.
Meltdown and Spectre are two techniques researchers have discovered that circumvent those protections, exposing nearly any data the computer processes, such as passwords, proprietary information, or encrypted communications.
Meltdown affects Intel processors works by breaking through the barrier that prevents applications from accessing arbitrary locations in kernel memory, Spectre affects Intel, AMD, and ARM processors, broadening its reach to include mobile phones, embedded devices, and pretty much anything with a chip in it. Spectre essentially tricks applications into accidentally disclosing information that would normally be inaccessible, safe inside their protected memory area.