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

USN-4325-1: Linux kernel vulnerabilities

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Ubuntu Security Notice USN-4325-1
April 07, 2020

linux-azure, linux-gcp, linux-gke-5.0, linux-oem-osp1, linux-oracle-5.0
vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gke-5.0: Linux kernel for Google Container Engine (GKE) systems
- linux-oem-osp1: Linux kernel for OEM processors
- linux-oracle-5.0: Linux kernel for Oracle Cloud systems

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 18.04 LTS:
linux-image-5.0.0-1014-oracle 5.0.0-1014.19
linux-image-5.0.0-1033-gke 5.0.0-1033.34
linux-image-5.0.0-1034-gcp 5.0.0-1034.35
linux-image-5.0.0-1036-azure 5.0.0-1036.38
linux-image-5.0.0-1047-oem-osp1 5.0.0-1047.52
linux-image-azure 5.0.0.1036.47
linux-image-gcp 5.0.0.1034.38
linux-image-gke-5.0 5.0.0.1033.21
linux-image-oem-osp1 5.0.0.1047.50
linux-image-oracle 5.0.0.1014.15

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/4325-1
CVE-2019-19046, CVE-2020-8428

Package Information:
  https://launchpad.net/ubuntu/+source/linux-azure/5.0.0-1036.38
  https://launchpad.net/ubuntu/+source/linux-gcp/5.0.0-1034.35
  https://launchpad.net/ubuntu/+source/linux-gke-5.0/5.0.0-1033.34
  https://launchpad.net/ubuntu/+source/linux-oem-osp1/5.0.0-1047.52
  https://launchpad.net/ubuntu/+source/linux-oracle-5.0/5.0.0-1014.19