USN-4484-1: Linux kernel vulnerability

Releases

• Ubuntu 18.04 ESM

Packages

• linux-aws-5.3 - Linux kernel for Amazon Web Services (AWS) systems
• linux-gke-5.3 - Linux kernel for Google Container Engine (GKE) systems
• linux-hwe - Linux hardware enablement (HWE) kernel
• linux-raspi2-5.3 - Linux kernel for Raspberry Pi (V8) systems

Details

It was discovered that the cgroup v2 subsystem in the Linux kernel did not
properly perform reference counting in some situations, leading to a NULL
pointer dereference. A local attacker could use this to cause a denial of
service or possibly gain administrative privileges.

Update instructions

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

Ubuntu 18.04

• linux-image-5.3.0-1032-raspi2 - 5.3.0-1032.34
• linux-image-5.3.0-1034-aws - 5.3.0-1034.36
• linux-image-5.3.0-1034-gke - 5.3.0-1034.36
• linux-image-5.3.0-66-generic - 5.3.0-66.60
• linux-image-5.3.0-66-lowlatency - 5.3.0-66.60
• linux-image-aws - 5.3.0.1034.33
• linux-image-gke-5.3 - 5.3.0.1034.19
• linux-image-gkeop-5.3 - 5.3.0.66.123
• linux-image-raspi2-hwe-18.04 - 5.3.0.1032.22

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

• CVE-2020-14356

Related notices

• USN-4483-1
• USN-4526-1