Several security issues were fixed in the kernel.
CAI Qian discovered that shared bind mounts in a mount namespace exponentially added entries without restriction to the Linux kernel’s mount table. A local attacker could use this to cause a denial of service (system crash). (CVE-2016-6213)
20 December 2016
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
CAI Qian discovered that shared bind mounts in a mount namespace exponentially added entries without restriction to the Linux kernel’s mount table. A local attacker could use this to cause a denial of service (system crash). (CVE-2016-6213)
It was discovered that a race condition existed in the procfs environ_read function in the Linux kernel, leading to an integer underflow. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2016-7916)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.