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

USN-5591-3: Linux kernel vulnerability

==========================================================================
Ubuntu Security Notice USN-5591-3
September 01, 2022

linux, linux-azure-4.15, linux-dell300x, linux-gcp-4.15, linux-kvm,
linux-snapdragon vulnerability
==========================================================================

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

- Ubuntu 18.04 LTS

Summary:

The system could be made to crash or run programs as an administrator.

Software Description:
- linux: Linux kernel
- linux-azure-4.15: Linux kernel for Microsoft Azure Cloud systems
- linux-dell300x: Linux kernel for Dell 300x platforms
- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors

Details:

It was discovered that the virtual terminal driver in the Linux kernel did not properly handle VGA console font changes, leading to an out-of-bounds write. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Update instructions:

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

Ubuntu 18.04 LTS:
linux-image-4.15.0-1052-dell300x 4.15.0-1052.57
linux-image-4.15.0-1126-kvm 4.15.0-1126.131
linux-image-4.15.0-1135-gcp 4.15.0-1135.151
linux-image-4.15.0-1136-snapdragon 4.15.0-1136.146
linux-image-4.15.0-1150-azure 4.15.0-1150.165
linux-image-4.15.0-192-generic 4.15.0-192.203
linux-image-4.15.0-192-generic-lpae 4.15.0-192.203
linux-image-4.15.0-192-lowlatency 4.15.0-192.203
linux-image-azure-lts-18.04 4.15.0.1150.120
linux-image-dell300x 4.15.0.1052.52
linux-image-gcp-lts-18.04 4.15.0.1135.151
linux-image-generic 4.15.0.192.177
linux-image-generic-lpae 4.15.0.192.177
linux-image-kvm 4.15.0.1126.119
linux-image-lowlatency 4.15.0.192.177
linux-image-snapdragon 4.15.0.1136.137
linux-image-virtual 4.15.0.192.177

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-5591-3
https://ubuntu.com/security/notices/USN-5591-1
CVE-2021-33656

Package Information:
https://launchpad.net/ubuntu/+source/linux/4.15.0-192.203
https://launchpad.net/ubuntu/+source/linux-azure-4.15/4.15.0-1150.165
https://launchpad.net/ubuntu/+source/linux-dell300x/4.15.0-1052.57
https://launchpad.net/ubuntu/+source/linux-gcp-4.15/4.15.0-1135.151
https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1126.131
https://launchpad.net/ubuntu/+source/linux-snapdragon/4.15.0-1136.146