RHSA-2016:0004: Important: kernel security update

The kernel packages contain the Linux kernel, the core of any Linuxoperating system. It was found that the x86 ISA (Instruction Set Architecture) is prone to a denial of service attack inside a virtualized environment in the form ofan infinite loop in the microcode due to the way (sequential) delivering ofbenign exceptions such as #AC (alignment check exception) and #DB (debugexception) is handled. A privileged user inside a guest could use theseflaws to create denial of service conditions on the host kernel.(CVE-2015-5307, CVE-2015-8104, Important)Red Hat would like to thank Ben Serebrin of Google Inc. for reporting theCVE-2015-5307 issue.All kernel users are advised to upgrade to these updated packages, whichcontain backported patches to correct these issues. The system must berebooted for this update to take effect.