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

USN-5484-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-5484-1
June 16, 2022

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

- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel

Details:

It was discovered that the Linux kernel did not properly restrict access to
the kernel debugger when booted in secure boot environments. A privileged
attacker could use this to bypass UEFI Secure Boot restrictions.
(CVE-2022-21499)

It was discovered that a race condition existed in the network scheduling
subsystem of the Linux kernel, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2021-39713)

It was discovered that some Intel processors did not completely perform
cleanup actions on multi-core shared buffers. A local attacker could
possibly use this to expose sensitive information. (CVE-2022-21123)

It was discovered that some Intel processors did not completely perform
cleanup actions on microarchitectural fill buffers. A local attacker could
possibly use this to expose sensitive information. (CVE-2022-21125)

It was discovered that some Intel processors did not properly perform
cleanup during specific special register write operations. A local attacker
could possibly use this to expose sensitive information. (CVE-2022-21166)

Update instructions:

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

Ubuntu 14.04 ESM:
linux-image-3.13.0-190-generic 3.13.0-190.241
linux-image-3.13.0-190-lowlatency 3.13.0-190.241
linux-image-generic 3.13.0.190.199
linux-image-lowlatency 3.13.0.190.199
linux-image-server 3.13.0.190.199
linux-image-virtual 3.13.0.190.199

Please note that fully mitigating processor vulnerabilities requires
corresponding processor microcode/firmware updates.

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-5484-1
CVE-2021-39713, CVE-2022-21123, CVE-2022-21125, CVE-2022-21166,
CVE-2022-21499