The vulnerability in the Linux kernel KVM arm64 code arises because flush_hyp_vcpu() copies the host vCPU context into the hypervisor's private vCPU without clearing the __hyp_running_vcpu field. ctxt_to_vcpu() expects this field to be NULL in guest contexts and uses it to resolve the vCPU via container_of(). Since flush_hyp_vcpu() does not clear __hyp_running_vcpu, a host pointer could be dereferenced at EL2, which is improper. The patch addresses this by clearing __hyp_running_vcpu after copying the context, preventing the misuse of the host pointer in the guest context.

The vulnerability could allow improper dereferencing of a host pointer at EL2 due to the __hyp_running_vcpu field not being cleared in the guest context. This may lead to incorrect hypervisor behavior or potential security issues related to context handling in the KVM arm64 virtualization environment. No known exploits in the wild have been reported.

A fix has been implemented in the Linux kernel to clear the __hyp_running_vcpu field after copying the host vCPU context in flush_hyp_vcpu(). Users should apply the official Linux kernel updates that include this patch. Since no explicit patch links or vendor advisories are provided, users should monitor the Linux kernel release notes and update accordingly. Patch status is not yet confirmed in this data — check the vendor advisory for current remediation guidance.