KVM Vulnerability in Hygon Family 18h CPUs

CVE-2026-64172

What is CVE-2026-64172?

A recently identified vulnerability in KVM's handling of IPI virtualization on Hygon Family 18h CPUs can cause significant delays in guest virtual machine execution. Derived from AMD Family 17h silicon, these CPUs may experience issues due to erratum #1235, where a stale IsRunning=1 bit could be read during ICR write emulation. This flaw leads to a failure in generating an AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit, resulting in hung virtual CPUs and unbounded delays in execution. Developers are advised to implement the workaround established for AMD Family 17h to mitigate potential risks.

References