A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS and 19.10.

USN-4319-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-4319-1
April 06, 2020

linux, linux-aws, linux-gcp, linux-gcp-5.3, linux-hwe, linux-kvm,
linux-oracle, linux-oracle-5.3, linux-raspi2, linux-raspi2-5.3
vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.10
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi2: Linux kernel for Raspberry Pi 2
- linux-gcp-5.3: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel
- linux-oracle-5.3: Linux kernel Oracle Cloud systems
- linux-raspi2-5.3: Linux kernel for Raspberry Pi 2

Details:

It was discovered that the IPMI message handler implementation in the Linux
kernel did not properly deallocate memory in certain situations. A local
attacker could use this to cause a denial of service (kernel memory
exhaustion). (CVE-2019-19046)

Al Viro discovered that the vfs layer in the Linux kernel contained a use-
after-free vulnerability. A local attacker could use this to cause a denial
of service (system crash) or possibly expose sensitive information (kernel
memory). (CVE-2020-8428)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 19.10:
linux-image-5.3.0-1014-oracle 5.3.0-1014.15
linux-image-5.3.0-1015-kvm 5.3.0-1015.16
linux-image-5.3.0-1016-aws 5.3.0-1016.17
linux-image-5.3.0-1017-gcp 5.3.0-1017.18
linux-image-5.3.0-1022-raspi2 5.3.0-1022.24
linux-image-5.3.0-46-generic 5.3.0-46.38
linux-image-5.3.0-46-generic-lpae 5.3.0-46.38
linux-image-5.3.0-46-lowlatency 5.3.0-46.38
linux-image-5.3.0-46-snapdragon 5.3.0-46.38
linux-image-aws 5.3.0.1016.18
linux-image-gcp 5.3.0.1017.18
linux-image-generic 5.3.0.46.39
linux-image-generic-lpae 5.3.0.46.39
linux-image-gke 5.3.0.1017.18
linux-image-kvm 5.3.0.1015.17
linux-image-lowlatency 5.3.0.46.39
linux-image-oracle 5.3.0.1014.15
linux-image-raspi2 5.3.0.1022.19
linux-image-snapdragon 5.3.0.46.39
linux-image-virtual 5.3.0.46.39

Ubuntu 18.04 LTS:
linux-image-5.3.0-1014-oracle 5.3.0-1014.15~18.04.1
linux-image-5.3.0-1017-gcp 5.3.0-1017.18~18.04.1
linux-image-5.3.0-1022-raspi2 5.3.0-1022.24~18.04.1
linux-image-5.3.0-46-generic 5.3.0-46.38~18.04.1
linux-image-5.3.0-46-generic-lpae 5.3.0-46.38~18.04.1
linux-image-5.3.0-46-lowlatency 5.3.0-46.38~18.04.1
linux-image-gcp-edge 5.3.0.1017.16
linux-image-generic-hwe-18.04 5.3.0.46.102
linux-image-generic-lpae-hwe-18.04 5.3.0.46.102
linux-image-lowlatency-hwe-18.04 5.3.0.46.102
linux-image-oracle-edge 5.3.0.1014.13
linux-image-raspi2-hwe-18.04 5.3.0.1022.11
linux-image-snapdragon-hwe-18.04 5.3.0.46.102
linux-image-virtual-hwe-18.04 5.3.0.46.102

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.

References:
  https://usn.ubuntu.com/4319-1
CVE-2019-19046, CVE-2020-8428

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.3.0-46.38
  https://launchpad.net/ubuntu/+source/linux-aws/5.3.0-1016.17
  https://launchpad.net/ubuntu/+source/linux-gcp/5.3.0-1017.18
  https://launchpad.net/ubuntu/+source/linux-kvm/5.3.0-1015.16
  https://launchpad.net/ubuntu/+source/linux-oracle/5.3.0-1014.15
  https://launchpad.net/ubuntu/+source/linux-raspi2/5.3.0-1022.24
  https://launchpad.net/ubuntu/+source/linux-gcp-5.3/5.3.0-1017.18~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-46.38~18.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle-5.3/5.3.0-1014.15~18.04.1
  https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1022.24~18.04.1