In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic: Take a refcount on IRQs referenced by last_lr_irq Referencing… (CVE-2026-98712)

The vulnerability in the Linux kernel affects the KVM arm64 vgic implementation. Specifically, referencing the last interrupt inserted in a List Register (LR) was fragile because the interrupt could disappear if an LPI was concurrently unmapped. This could lead to use-after-free or similar issues related to interrupt handling. The resolution was to increase the reference count on the interrupt when setting last_lr_irq and to drop the reference count when LPIs are reclaimed in vgic_prune_ap_list().

The vulnerability could cause instability or incorrect behavior in the KVM arm64 virtual interrupt controller due to referencing interrupts that might have been concurrently unmapped. This could potentially lead to kernel crashes or undefined behavior in virtualized environments using KVM on arm64 architectures. No known exploits in the wild have been reported.

An official fix has been applied to the Linux kernel to address this issue by properly managing reference counts on interrupts referenced by last_lr_irq. Users should update to a Linux kernel version that includes this fix. Since this is a kernel-level vulnerability, applying the updated kernel version is the recommended remediation.