The issues that been found to affect Ubuntu 15.10 (Wily Werewolf) operating system are best explained in a few security notifications: CVE-2015-8104, CVE-2015-7799, CVE-2015-7872, CVE-2015-7884, and CVE-2015-7885.
“Jan Beulich discovered that the KVM svm hypervisor implementation in the Linux kernel did not properly catch Debug exceptions on AMD processors. An attacker in a guest virtual machine could use this to cause a denial of service (system crash) in the host OS” reads the security notice.
This is just one of the vulnerabilities that have been fixed with the latest update. The security flaws can be fixed if you upgrade your system to the linux-image-4.2.0-21-generic (4.2.0-21.25) package. Don’t forget to reboot your computer after the upgrade. It can be postponed, but the update needs the restart in order to be completed. A simple log out procedure is not sufficient.
ATTENTION: Due to an unavoidable ABI change, the kernel packages have a new version number, which will force you to reinstall and recompile all third-party kernel modules you might have installed. Moreover, if you use the Linux-restricted-modules package, you have to update it as well to get modules that work with the new Linux kernel version.
Submitted by: Arnfried Walbrecht