Ubuntu Security Notice 2776-1 – It was discovered that the Linux kernel did not check if a new IPv6 MTU set by a user space application was valid. A remote attacker could forge a route advertisement with an invalid MTU that a user space daemon like NetworkManager would honor and apply to the kernel, causing a denial of service. It was discovered that virtio networking in the Linux kernel did not handle fragments correctly, leading to kernel memory corruption. A remote attacker could use this to cause a denial of service (system crash) or possibly execute code with administrative privileges. Various other issues were also addressed.