Several security issues were fixed in the kernel.
Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel did not properly validate meta block groups. An attacker with physical access could use this to specially craft an ext4 image that causes a denial of service (system crash). (CVE-2016-10208)
15 March 2017
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel did not properly validate meta block groups. An attacker with physical access could use this to specially craft an ext4 image that causes a denial of service (system crash). (CVE-2016-10208)
It was discovered that the Linux kernel did not clear the setgid bit during a setxattr call on a tmpfs filesystem. A local attacker could use this to gain elevated group privileges. (CVE-2017-5551)
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.
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