An Intel Microcode security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS, 23.04, and 23.10.

[USN-6485-1] Intel Microcode vulnerability

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Ubuntu Security Notice USN-6485-1
November 17, 2023

intel-microcode vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 23.10
- Ubuntu 23.04
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)

Summary:

The system could be made to crash or expose sensitive information under certain
conditions.

Software Description:
- intel-microcode: Processor microcode for Intel CPUs

Details:

Benoit Morgan, Paul Grosen, Thais Moreira Hamasaki, Ke Sun, Alyssa Milburn,
Hisham Shafi, Nir Shlomovich, Tavis Ormandy, Daniel Moghimi, Josh Eads, Salman
Qazi, Alexandra Sandulescu, Andy Nguyen, Eduardo Vela, Doug Kwan, and Kostik
Shtoyk discovered that some Intel(R) Processors did not properly handle certain
sequences of processor instructions. A local attacker could possibly use this to
cause a core hang (resulting in a denial of service), gain access to sensitive
information or possibly escalate their privileges.

Update instructions:

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

Ubuntu 23.10:
intel-microcode 3.20231114.0ubuntu0.23.10.1

Ubuntu 23.04:
intel-microcode 3.20231114.0ubuntu0.23.04.1

Ubuntu 22.04 LTS:
intel-microcode 3.20231114.0ubuntu0.22.04.1

Ubuntu 20.04 LTS:
intel-microcode 3.20231114.0ubuntu0.20.04.1

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
intel-microcode 3.20231114.0ubuntu0.18.04.1+esm1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
intel-microcode 3.20231114.0ubuntu0.16.04.1+esm1

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-6485-1
CVE-2023-23583

Package Information:
https://launchpad.net/ubuntu/+source/intel-microcode/3.20231114.0ubuntu0.23.10.1
https://launchpad.net/ubuntu/+source/intel-microcode/3.20231114.0ubuntu0.23.04.1
https://launchpad.net/ubuntu/+source/intel-microcode/3.20231114.0ubuntu0.22.04.1
https://launchpad.net/ubuntu/+source/intel-microcode/3.20231114.0ubuntu0.20.04.1