The msr_mtrr_valid function in arch/x86/kvm/mtrr.c in the Linux kernel before 4.6.1 supports MSR 0x2f8, which allows guest OS users to read or write to the kvm_arch_vcpu data structure, and consequently obtain sensitive information or cause a denial of service (system crash), via a crafted ioctl call.

Affected: Ubuntu:14.04:LTS: linux-lts-wily

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. (CVE-2016-3713)

Philip Pettersson discovered that the Linux kernel's ASN.1 DER decoder did not properly process certificate files with tags of indefinite length. A local unprivileged attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges. (CVE-2016-0758)