Ubuntu Security Notice 2978-2 – USN-2978-1 fixed vulnerabilities in the Linux kernel for Ubuntu 15.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 15.10 for Ubuntu 14.04 LTS. David Matlack discovered that the Kernel-based Virtual Machine (KVM) implementation in the Linux kernel did not properly restrict variable Memory Type Range Registers (MTRR) in KVM guests. A privileged user in a guest VM could use this to cause a denial of service (system crash) in the host, expose sensitive information from the host, or possibly gain administrative privileges in the host. Various other issues were also addressed.