Several security issues were fixed in the Linux kernel.
Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory.
9 January 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the Linux kernel.
Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory.
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.