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USN-4727-1: Linux kernel vulnerability

10 February 2021

The system could be made to crash or run programs as an administrator.



  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe-5.8 - Linux hardware enablement (HWE) kernel
  • linux-kvm - Linux kernel for cloud environments
  • linux-oem-5.6 - Linux kernel for OEM systems
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi - Linux kernel for Raspberry Pi (V8) systems


Alexander Popov discovered that multiple race conditions existed in the
AF_VSOCK implementation in the Linux kernel. A local attacker could use
this to cause a denial of service (system crash) or execute arbitrary code.

Update instructions

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

Ubuntu 20.10
Ubuntu 20.04

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.