Spectre and Meltdown Expose Privileged Memory Through Speculative Execution

Researchers disclosed the Spectre and Meltdown CPU side-channel attacks, showing that speculative and out-of-order execution can transiently bypass security checks and leave protected data observable through microarchitectural state such as processor caches. The flaws affect isolation boundaries intended to protect kernel, process, and virtual-machine memory; Meltdown is tracked as CVE-2017-5754 and primarily affects Intel processors, while Spectre variants affect a broader range of Intel, AMD, and ARM designs.

Spectre Variant 2, CVE-2017-5715, uses branch-target injection to induce privileged code to speculatively access data and expose it through cache behavior, potentially crossing syscall and guest/host boundaries. Red Hat rated the vulnerability Important with a CVSS v3 score of 5.6 and released kernel fixes for supported Red Hat Enterprise Linux 5, 6, and 7 streams; organizations should apply vendor firmware, kernel, and virtualization mitigations appropriate to their processors and workloads.