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Ubuntu 20.04 & 18.04 USN-5091-2 Critical: Multiple Kernel Issues

ubuntu
Calendar Grey September 30, 2021
Dist Ubuntu Esm H88
Multiple security issues addressed in Ubuntu update USN-5091-2 with kernel update recommendations. Stay protected!
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 systems

- linux-raspi-5.4: Linux kernel for Raspberry Pi systems

Details:

Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk

discovered that the BPF verifier in the Linux kernel missed possible

mispredicted branches due to type confusion, allowing a side-channel

attack. An attacker could use this to expose sensitive information.

(CVE-2021-33624)

It was discovered that the tracing subsystem in the Linux kernel did not

properly keep track of per-cpu ring buffer state. A privileged attacker

could use this to cause a denial of service. (CVE-2021-3679)

It was discovered that the Virtio console implementation in the Linux

kernel did not properly validate input lengths in some situations. A local

attacker could possibly use this to cause a denial of service (system

crash). (CVE-2021-38160)

Michael Wakabayashi discovered that the NFSv4 client impl...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory denial of service Ubuntu kernel issue side-channel linux-raspi

Update Instructions

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1044-raspi    5.4.0-1044.48
  linux-image-raspi               5.4.0.1044.79
  linux-image-raspi2              5.4.0.1044.79

Ubuntu 18.04 LTS:
  linux-image-5.4.0-1044-raspi    5.4.0-1044.48~18.04.1
  linux-image-raspi-hwe-18.04     5.4.0.1044.47

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-5091-2

https://ubuntu.com/security/notices/USN-5091-1

CVE-2021-33624, CVE-2021-3679, CVE-2021-38160, CVE-2021-38199,

CVE-2021-38204

Severity
critical
Lowest
Low
Medium
High
Critical

September 30, 2021

Topics%20covered

Topics Covered

security advisory denial of service Ubuntu kernel issue side-channel linux-raspi

Package Information

https://launchpad.net/ubuntu/+source/linux-raspi/5.4.0-1044.48
https://launchpad.net/ubuntu/+source/linux-raspi-5.4/5.4.0-1044.48~18.04.1

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