CVE-2026-64287

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU

flush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU

on every run. The vGIC list register save and restore use used_lrs as

their loop bound and expect it to stay within the number of implemented

list registers. While this is generally the case, flush_hyp_vcpu()

copies vgic_v3 verbatim and does not enforce this, so a value provided

by the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2

(host -> EL2).

Fix by clamping used_lrs to the number of implemented list registers

after the copy, as the trusted path already does in

vgic_flush_lr_state(). The number of implemented list registers is

constant after init, so it is replicated once from

kvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on

every entry.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References