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

USN-5595-1: Linux kernel vulnerabilities

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Ubuntu Security Notice USN-5595-1
September 02, 2022

linux-aws-5.4, linux-azure-5.4 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-aws-5.4: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure-5.4: Linux kernel for Microsoft Azure cloud systems

Details:

Asaf Modelevsky discovered that the Intel(R) 10GbE PCI Express (ixgbe)
Ethernet driver for the Linux kernel performed insufficient control flow
management. A local attacker could possibly use this to cause a denial of service. (CVE-2021-33061)

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. (CVE-2021-33656)

Update instructions:

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

Ubuntu 18.04 LTS:
linux-image-5.4.0-1084-aws 5.4.0-1084.91~18.04.1
linux-image-5.4.0-1090-azure 5.4.0-1090.95~18.04.1
linux-image-aws 5.4.0.1084.64
linux-image-azure 5.4.0.1090.67

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-5595-1
CVE-2021-33061, CVE-2021-33656

Package Information:
https://launchpad.net/ubuntu/+source/linux-aws-5.4/5.4.0-1084.91~18.04.1

https://launchpad.net/ubuntu/+source/linux-azure-5.4/5.4.0-1090.95~18.04.1