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             AUSCERT External Security Bulletin Redistribution

                  USN-4727-1: Linux kernel vulnerability
                             10 February 2021


        AusCERT Security Bulletin Summary

Product:           Linux kernel
Publisher:         Ubuntu
Operating System:  Ubuntu
                   Linux variants
Impact/Access:     Root Compromise                 -- Existing Account
                   Execute Arbitrary Code/Commands -- Existing Account
                   Increased Privileges            -- Existing Account
                   Denial of Service               -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-26708  

Original Bulletin: 

Comment: This advisory references vulnerabilities in the Linux kernel that 
         also affect distributions other than Ubuntu. It is recommended that
         administrators running Linux check for an updated version of the 
         kernel for their system.

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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.

  o Ubuntu 20.10
  o Ubuntu 20.04 LTS


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

Ubuntu 20.10

  o linux-image-5.8.0-1015-raspi - 5.8.0-1015.18
  o linux-image-5.8.0-1015-raspi-nolpae - 5.8.0-1015.18
  o linux-image-5.8.0-1018-kvm - 5.8.0-1018.20
  o linux-image-5.8.0-1020-oracle - 5.8.0-1020.21
  o linux-image-5.8.0-1022-azure - 5.8.0-1022.24
  o linux-image-5.8.0-1022-gcp - 5.8.0-1022.23
  o linux-image-5.8.0-1023-aws - 5.8.0-1023.25
  o linux-image-5.8.0-43-generic - 5.8.0-43.49
  o linux-image-5.8.0-43-generic-64k - 5.8.0-43.49
  o linux-image-5.8.0-43-generic-lpae - 5.8.0-43.49
  o linux-image-5.8.0-43-lowlatency - 5.8.0-43.49
  o linux-image-aws -
  o linux-image-azure -
  o linux-image-gcp -
  o linux-image-generic -
  o linux-image-generic-64k -
  o linux-image-generic-lpae -
  o linux-image-gke -
  o linux-image-kvm -
  o linux-image-lowlatency -
  o linux-image-oracle -
  o linux-image-raspi -
  o linux-image-raspi-nolpae -
  o linux-image-virtual -

Ubuntu 20.04

  o linux-image-5.6.0-1047-oem - 5.6.0-1047.51
  o linux-image-5.8.0-43-generic - 5.8.0-43.49~20.04.1
  o linux-image-5.8.0-43-generic-lpae - 5.8.0-43.49~20.04.1
  o linux-image-5.8.0-43-lowlatency - 5.8.0-43.49~20.04.1
  o linux-image-generic-64k-hwe-20.04 -
  o linux-image-generic-hwe-20.04 -
  o linux-image-generic-lpae-hwe-20.04 -
  o linux-image-lowlatency-hwe-20.04 -
  o linux-image-oem-20.04 -
  o linux-image-virtual-hwe-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.


  o CVE-2021-26708

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