On February 22, fixes for CVE-2017-5715 were released into the Ubuntu Xenial kernel version 4.4.0-116.140. This CVE, also known as "Spectre," is caused by flaws in the design of speculative execution hardware in the computer's CPU, and could be used to access sensitive information in kernel memory.
72d363acb6dc156e006e909ac1b2d43d8475b46890268147bf31b5fba6a2cc9e