Kernel Vulnerability in Linux Affecting AMD CPUs

CVE-2026-64229

What is CVE-2026-64229?

A vulnerability has been identified in the Linux kernel that affects systems where the PCID (Process Context Identifier) feature is disabled, particularly in AMD CPUs supporting TLB (Translation Lookaside Buffer) invalidation. When the system boots with the 'nopcid' option, broadcast TLB flushing can lead to serious issues, including general protection faults due to incorrect handling of CPU features. Proper checks are lacking, leading to attempts to issue broadcast TLB flush commands with a non-zero PCID, resulting in crashes and potential exposure of the system to risks. This emphasizes the need for correct dependency handling of CPU features in kernel operations.

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