--- title: 'USN-3718-1: Linux kernel regression | Ubuntu security notices' description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/notices/USN-3718-1 --- 1. [Ubuntu Security Notices](https://ubuntu.com/security/notices) 2. USN-3718-1 --- # USN-3718-1: Linux kernel regression Publication date 21 July 2018 Overview A regression that caused boot failures was fixed in the Linux kernel. Releases [18.04 LTS](https://ubuntu.com/security/notices?release=bionic) --- Open side navigation ## Packages * [linux](https://ubuntu.com/security/cves?package=linux) - Linux kernel * [linux-aws](https://ubuntu.com/security/cves?package=linux-aws) - Linux kernel for Amazon Web Services (AWS) systems * [linux-azure](https://ubuntu.com/security/cves?package=linux-azure) - Linux kernel for Microsoft Azure Cloud systems * [linux-gcp](https://ubuntu.com/security/cves?package=linux-gcp) - Linux kernel for Google Cloud Platform (GCP) systems * [linux-kvm](https://ubuntu.com/security/cves?package=linux-kvm) - Linux kernel for cloud environments * [linux-oem](https://ubuntu.com/security/cves?package=linux-oem) - Linux kernel for OEM processors ## Details USN-3695-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. Unfortunately, the fix for [CVE-2018-1108](https://ubuntu.com/security/CVE-2018-1108) introduced a regression where insufficient early entropy prevented services from starting, leading in some situations to a failure to boot, This update addresses the issue. We apologize for the inconvenience. Original advisory details: Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. ([CVE-2018-1108](https://ubuntu.com/security/CVE-2018-1108)) Wen Xu discovered that the ext4 file system implementation in the Linux kernel did not properly initialize the crc32c checksum driver. A local attacker could use this to cause a denial of service (system crash). ( --- Show more ## Update instructions After a standard system update you need to reboot your computer to make all the necessary changes. [Learn more about how to get the fixes.](https://ubuntu.com/security/cves/about#security) 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. The problem can be corrected by updating your system to the following package versions: | Ubuntu Release | Package Version | | --- | --- | | 18.04 LTS bionic | [linux-image-4.15.0-1014-gcp](https://launchpad.net/ubuntu/+source/linux-gcp) –  [4.15.0-1014.14](https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1014.14) | | | | [linux-image-4.15.0-1016-aws](https://launchpad.net/ubuntu/+source/linux-aws) –  [4.15.0-1016.16](https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1016.16) | | | | [linux-image-4.15.0-1016-kvm](https://launchpad.net/ubuntu/+source/linux-aws) –  [4.15.0-1016.16](https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1016.16) | | | | [linux-image-4.15.0-29-generic](https://launchpad.net/ubuntu/+source/linux) –  [4.15.0-29.31](https://launchpad.net/ubuntu/+source/linux/4.15.0-29.31) | | | | [linux-image-4.15.0-29-generic-lpae](https://launchpad.net/ubuntu/+source/linux) –  [4.15.0-29.31](https://launchpad.net/ubuntu/+source/linux/4.15.0-29.31) | | | | [linux-image-4.15.0-29-lowlatency](https://launchpad.net/ubuntu/+source/linux) –  [4.15.0-29.31](https://launchpad.net/ubuntu/+source/linux/4.15.0-29.31) | | | | [linux-image-4.15.0-29-snapdragon](https://launchpad.net/ubuntu/+source/linux) –  [4.15.0-29.31](https://launchpad.net/ubuntu/+source/linux/4.15.0-29.31) | | | --- ### Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. [Get Ubuntu Pro](https://ubuntu.com/pro) ## References * * --- Have additional questions? [Talk to a member of the team ›](https://wiki.ubuntu.com/SecurityTeam/FAQ?_ga=2.242131138.1744859116.1742138161-1500419473.1726851136&_gl=1*161muja*_gcl_au*MzUyMTIzNjI1LjE3MzYyNDQ4NTE.#Contact)