A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS and 20.04 LTS.

[USN-6495-2] Linux kernel vulnerabilities

==========================================================================
Ubuntu Security Notice USN-6495-2
November 30, 2023

linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gkeop
vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)

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-gkeop: Linux kernel for Google Container Engine (GKE) systems
- linux-azure-5.4: Linux kernel for Microsoft Azure cloud systems
- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) systems

Details:

Yu Hao discovered that the UBI driver in the Linux kernel did not properly
check for MTD with zero erasesize during device attachment. A local
privileged attacker could use this to cause a denial of service (system
crash). (CVE-2023-31085)

Manfred Rudigier discovered that the Intel(R) PCI-Express Gigabit (igb)
Ethernet driver in the Linux kernel did not properly validate received
frames that are larger than the set MTU size, leading to a buffer overflow
vulnerability. An attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-45871)

Update instructions:

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

Ubuntu 20.04 LTS:
linux-image-5.4.0-1081-gkeop 5.4.0-1081.85
linux-image-5.4.0-1118-gcp 5.4.0-1118.127
linux-image-5.4.0-1120-azure 5.4.0-1120.127
linux-image-azure-lts-20.04 5.4.0.1120.113
linux-image-gcp-lts-20.04 5.4.0.1118.120
linux-image-gkeop 5.4.0.1081.79
linux-image-gkeop-5.4 5.4.0.1081.79

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
linux-image-5.4.0-1118-gcp 5.4.0-1118.127~18.04.1
linux-image-5.4.0-1120-azure 5.4.0-1120.127~18.04.1
linux-image-azure 5.4.0.1120.93
linux-image-gcp 5.4.0.1118.94

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://ubuntu.com/security/notices/USN-6495-2
https://ubuntu.com/security/notices/USN-6495-1
CVE-2023-31085, CVE-2023-45871

Package Information:
https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1120.127
https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1118.127
https://launchpad.net/ubuntu/+source/linux-gkeop/5.4.0-1081.85