Ubuntu Security Notice USN-5465-1
June 08, 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


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


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.

Aaron Adams discovered that the netfilter subsystem in the Linux kernel did
not properly handle the removal of stateful expressions in some situations,
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.

Jann Horn discovered that the Linux kernel did not properly enforce seccomp
restrictions in some situations. A local attacker could use this to bypass
intended seccomp sandbox restrictions. (CVE-2022-30594)

Update instructions:

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

Ubuntu 16.04 ESM:
  linux-image-4.4.0-1108-kvm      4.4.0-1108.118
  linux-image-4.4.0-1143-aws      4.4.0-1143.158
  linux-image-4.4.0-227-generic   4.4.0-227.261
  linux-image-4.4.0-227-lowlatency  4.4.0-227.261

Ubuntu 14.04 ESM:
  linux-image-4.4.0-1107-aws      4.4.0-1107.113
  linux-image-4.4.0-227-generic   4.4.0-227.261~14.04.1
  linux-image-4.4.0-227-lowlatency  4.4.0-227.261~14.04.1

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.

  CVE-2022-1966, CVE-2022-21499, CVE-2022-30594