At the start of 2018, Google researchers revealed CPU hardware vulnerabilities called Meltdown and Spectre which affected almost all computers on the market.
Meltdown primarily affects Intel processors, while Spectre affects Intel, AMD and ARM processors. Daniel Gruss, one of the researchers that discovered the flaw at Graz University of Technology described Meltdown as "one of the worst CPU bugs ever found".
Although these are both primarily hardware vulnerabilities, they communicate with the operating system to access locations in its memory space.
Read next: Meltdown and Spectre chip flaw timeline
Meltdown, Google explains, "breaks the most fundamental isolation between user applications and the operating system. This allows a program to access the memory, and also the secrets, of other programs and the operating system."
Spectre meanwhile "breaks the isolation between different applications" – "it allows an attacker to trick error-free programs, which follow best practices, into leaking their secrets.