Several security issues were fixed in the kernel.
It was discovered that the Linux kernel did not check if a new IPv6 MTU set by a user space application was valid. A remote attacker could forge a route advertisement with an invalid MTU that a user space daemon like NetworkManager would honor and apply to the kernel, causing a denial of service. (CVE-2015-0272)
19 October 2015
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
It was discovered that the Linux kernel did not check if a new IPv6 MTU set by a user space application was valid. A remote attacker could forge a route advertisement with an invalid MTU that a user space daemon like NetworkManager would honor and apply to the kernel, causing a denial of service. (CVE-2015-0272)
It was discovered that virtio networking in the Linux kernel did not handle fragments correctly, leading to kernel memory corruption. A remote attacker could use this to cause a denial of service (system crash) or possibly execute code with administrative privileges. (CVE-2015-5156)
It was discovered that the Reliable Datagram Sockets (RDS) implementation in the Linux kernel did not verify sockets were properly bound before attempting to send a message, which could cause a NULL pointer dereference. An attacker could use this to cause a denial of service (system crash). (CVE-2015-6937)
Ben Hutchings discovered that the Advanced Union Filesystem (aufs) for the Linux kernel did not correctly handle references of memory mapped files from an aufs mount. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges. (CVE-2015-7312)
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. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.
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