Linux Kernel Vulnerability Allows VM Escape on Intel and AMD Systems

A newly reported Linux kernel issue, tracked as CVE-2026-53359 and dubbed Januscape, can be exploited by a guest VM to corrupt host state and gain execution on the underlying system via the KVM shadow MMU. This matters for multi-tenant x86 cloud environments—especially those with nested virtualization—because successful exploitation can lead to full host compromise, denial of service, or root-level code execution. Researchers note the flaw was present for 16 years and has been patched in the mainline kernel as of June 19.