Spectre

Definitions

1. A class of hardware vulnerabilities (disclosed January 2018) that exploit speculative execution in modern CPUs to trick a process into leaking data from its own or other processes' memory through timing side channels. Unlike Meltdown, Spectre affects nearly all modern processors (Intel, AMD, ARM) and is fundamentally harder to mitigate, requiring compiler-level changes (retpolines), microcode updates, and process isolation techniques like site isolation in browsers.

   In plain English: A hardware flaw in nearly all modern processors that lets an attacker trick the CPU into revealing secret data it shouldn't have access to.

   Example: "After Spectre, Chrome moved every site into its own renderer process because you can't trust a CPU branch predictor not to leak cross-origin data."

Related Terms

• VLAN
• L1 Cache
• L2 Cache
• Machine Instruction
• Memory Alignment
• Memory Fence
• Performance Counter
• Program Counter