The new Linux kernel security update is available for all users of the Ubuntu 16.04 LTS (Xenial Xerus) operating system series and its derivatives, affecting all those using the original Linux 4.4 kernel. If you upgraded your Ubuntu 16.04 LTS installations to the Linux 4.15 kernel from Ubuntu 18.04 LTS (Bionic Beaver), you aren’t affected. The security patch addresses a total of four flaws, including a use-after-free vulnerability (CVE-2018-14734) discovered by Noam Rathaus in the Infiniband implementation, letting attackers to crash the system via a denial of service, as well as an integer overflow (CVE-2018-16658) in the CD-ROM driver, which could allow a local attacker to expose sensitive information.