The new Azure kernel is available for Ubuntu 18.04 LTS (Bionic Beaver) and Ubuntu 16.04 LTS (Xenial Xerus) operating system series and addresses the side-channel attack discovered by Jann Horn and Ken Johnson, known as Spectre Variant 4 (CVE-2018-3639), which could allow a local attacker to expose sensitive information. Also discovered by Jann Horn, the new Azure kernel fixes the original Spectre vulnerability (CVE-2017-5715) and a use-after-free vulnerability (CVE-2018-17182) found in the vmacache subsystem, which could let a local attacker crash the system or execute arbitrary code.