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Ubuntu 20.04: 5071-3 Critical: Kernel Use-After-Free And DoS Exploits

ubuntu
Calendar Grey September 21, 2021
Dist Ubuntu Esm H88
Multiple vulnerabilities addressed in the Linux kernel for Raspberry Pi devices, affecting both Ubuntu 20.04 and 18.04 LTS distributions.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-raspi: Linux kernel for Raspberry Pi (V8) systems

- linux-raspi-5.4: Linux kernel for Raspberry Pi (V8) systems

Details:

It was discovered that the KVM hypervisor implementation in the Linux

kernel did not properly perform reference counting in some situations,

leading to a use-after-free vulnerability. An attacker who could start and

control a VM could possibly use this to expose sensitive information or

execute arbitrary code. (CVE-2021-22543)

Murray McAllister discovered that the joystick device interface in the

Linux kernel did not properly validate data passed via an ioctl(). A local

attacker could use this to cause a denial of service (system crash) or

possibly execute arbitrary code on systems with a joystick device

registered. (CVE-2021-3612)

Topics%20covered

Topics Covered

security advisory DoS kernel ubuntu use-after-free linux-raspi

Update Instructions

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1043-raspi    5.4.0-1043.47
  linux-image-raspi               5.4.0.1043.78
  linux-image-raspi2              5.4.0.1043.78

Ubuntu 18.04 LTS:
  linux-image-5.4.0-1043-raspi    5.4.0-1043.47~18.04.1
  linux-image-raspi-hwe-18.04     5.4.0.1043.46

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

https://ubuntu.com/security/notices/USN-5071-3

https://ubuntu.com/security/notices/USN-5071-1

CVE-2021-22543, CVE-2021-3612

Severity
critical
Lowest
Low
Medium
High
Critical

September 22, 2021

Topics%20covered

Topics Covered

security advisory DoS kernel ubuntu use-after-free linux-raspi

Package Information

https://launchpad.net/ubuntu/+source/linux-raspi/5.4.0-1043.47
https://launchpad.net/ubuntu/+source/linux-raspi-5.4/5.4.0-1043.47~18.04.1

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