Security researcher claims they found KVM guest-host escape flaw

Security researcher Paulos Yibelo has claimed a zero-day KVM guest-to-host escape affecting Firecracker MicroVMs used by Vercel's sandbox. The flaw, if confirmed, would allow a guest VM to gain root on the host and could impact many KVM-based cloud and virtualization deployments; public details are sparse and responsible disclosure and patching are still pending.