A Linux kernel security update has been released for Ubuntu Linux 14.04 ESM and 16.04 ESM.

USN-5557-1: Linux kernel vulnerabilities

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Ubuntu Security Notice USN-5557-1
August 09, 2022

linux, linux-aws, linux-kvm, linux-lts-xenial vulnerabilities
==========================================================================

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

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

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-kvm: Linux kernel for cloud environments
- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

Zhenpeng Lin discovered that the network packet scheduler implementation in
the Linux kernel did not properly remove all references to a route filter
before freeing it in some situations. A local attacker could use this to
cause a denial of service (system crash) or execute arbitrary code.
(CVE-2022-2588)

It was discovered that the netfilter subsystem of the Linux kernel did not
prevent one nft object from referencing an nft set in another nft table,
leading to a use-after-free vulnerability. A local attacker could use this
to cause a denial of service (system crash) or execute arbitrary code.
(CVE-2022-2586)

Update instructions:

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

Ubuntu 16.04 ESM:
linux-image-4.4.0-1112-kvm 4.4.0-1112.122
linux-image-4.4.0-1147-aws 4.4.0-1147.162
linux-image-4.4.0-231-generic 4.4.0-231.265
linux-image-4.4.0-231-lowlatency 4.4.0-231.265
linux-image-aws 4.4.0.1147.151
linux-image-generic 4.4.0.231.237
linux-image-kvm 4.4.0.1112.109
linux-image-lowlatency 4.4.0.231.237
linux-image-virtual 4.4.0.231.237

Ubuntu 14.04 ESM:
linux-image-4.4.0-1111-aws 4.4.0-1111.117
linux-image-4.4.0-231-generic 4.4.0-231.265~14.04.1
linux-image-4.4.0-231-lowlatency 4.4.0-231.265~14.04.1
linux-image-aws 4.4.0.1111.108
linux-image-generic-lts-xenial 4.4.0.231.201
linux-image-lowlatency-lts-xenial 4.4.0.231.201
linux-image-virtual-lts-xenial 4.4.0.231.201

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-5557-1
CVE-2022-2586, CVE-2022-2588