KVM Vulnerability in Linux Kernel Affecting Hyper-V Send IPI Hypercalls

CVE-2025-21779

Summary

A vulnerability in the KVM component of the Linux kernel could allow malicious actors to exploit Hyper-V's SEND_IPI hypercalls. This flaw occurs when the local Advanced Programmable Interrupt Controller (APIC) is not properly managed, leading to potential system crashes or instability. By advertising the support for these hypercalls only when the local APIC is emulated by KVM, the vulnerability is mitigated. It is essential for administrators to ensure they are running an updated version of the Linux kernel to avoid exploitation through this flaw, which could expose systems to severe operational risks.

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