Ubuntu 21.04 USN-4977-1 Critical: Linux Kernel Denial of Service

ubuntu

June 2, 2021

Several security issues were fixed in the Linux kernel.

Summary

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-azure: Linux kernel for Microsoft Azure Cloud systems

- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems

- linux-kvm: Linux kernel for cloud environments

- linux-oracle: Linux kernel for Oracle Cloud systems

Details:

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the

Linux kernel contained a reference counting error. A local attacker could

use this to cause a denial of service (system crash). (CVE-2020-25670)

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the

Linux kernel did not properly deallocate memory in certain error

situations. A local attacker could use this to cause a denial of service

(memory exhaustion). (CVE-2020-25671, CVE-2020-25672)

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the

Li...

Read the Full Advisory

Topics Covered

security advisory denial of service critical issue kernel update ubuntu linux kernel

Update Instructions

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

Ubuntu 21.04:
  linux-image-5.11.0-1006-azure   5.11.0-1006.6
  linux-image-5.11.0-1007-oracle  5.11.0-1007.7
  linux-image-5.11.0-1008-aws     5.11.0-1008.8
  linux-image-5.11.0-1008-gcp     5.11.0-1008.9
  linux-image-5.11.0-1008-kvm     5.11.0-1008.8
  linux-image-5.11.0-18-generic   5.11.0-18.19
  linux-image-5.11.0-18-generic-64k  5.11.0-18.19
  linux-image-5.11.0-18-generic-lpae  5.11.0-18.19
  linux-image-5.11.0-18-lowlatency  5.11.0-18.19
  linux-image-aws                 5.11.0.1008.8
  linux-image-azure               5.11.0.1006.6
  linux-image-gcp                 5.11.0.1008.8
  linux-image-generic             5.11.0.18.19
  linux-image-generic-64k         5.11.0.18.19
  linux-image-generic-lpae        5.11.0.18.19
  linux-image-gke                 5.11.0.1008.8
  linux-image-kvm                 5.11.0.1008.8
  linux-image-lowlatency          5.11.0.18.19
  linux-image-oracle              5.11.0.1007.7
  linux-image-virtual             5.11.0.18.19

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.