ITScape KVM/arm64 Escape Flaw Exposes Hosts to Guest-Led Kernel RCE

A critical guest-to-host escape vulnerability in KVM on arm64 systems, tracked as CVE-2026-46316 and dubbed ITScape, was publicly disclosed with working proof-of-concept exploit code. Researcher Hyunwoo Kim reported that the flaw resides in the in-kernel vGIC-ITS implementation, where a race condition and double-put use-after-free in vgic_its_invalidate_cache() can be triggered entirely from an untrusted guest VM, allowing execution of commands on the host with kernel privileges.

The issue affects arm64 Linux kernels spanning builds from late April 2024 through early June 2026 and raises particular concern for multi-tenant public cloud environments running unpatched arm64 KVM hosts. The published PoC reportedly demonstrates host-kernel code execution on aarch64, including creation of a root-owned /ITScape file on the host, while Linux kernel maintainers have already merged a fix that changes vgic_put_irq() handling based on the return value of xa_erase(). The disclosure also advises applying additional related patches, including one addressing CVE-2026-46317.