Ubuntu Security Notice 2684-1 – A flaw was discovered in the kvm (kernel virtual machine) subsystem’s kvm_apic_has_events function. A unprivileged local user could exploit this flaw to cause a denial of service (system crash). Daniel Borkmann reported a kernel crash in the Linux kernel’s BPF filter JIT optimization. A local attacker could exploit this flaw to cause a denial of service (system crash). A flaw was discovered in how the Linux kernel handles invalid UDP checksums. A remote attacker could exploit this flaw to cause a denial of service using a flood of UDP packets with invalid checksums. Various other issues were also addressed.