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A Linux kernel security update has been released for Ubuntu Linux 23.04.



[USN-6220-1] Linux kernel vulnerabilities


==========================================================================
Ubuntu Security Notice USN-6220-1
July 12, 2023

linux-azure, linux-gcp, linux-ibm, linux-oracle vulnerability
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 23.04

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-ibm: Linux kernel for IBM cloud systems
- linux-oracle: Linux kernel for Oracle Cloud systems

Details:

Hangyu Hua discovered that the Flower classifier implementation in the
Linux kernel contained an out-of-bounds write vulnerability. An attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2023-35788, LP: #2023577)

It was discovered that for some Intel processors the INVLPG instruction
implementation did not properly flush global TLB entries when PCIDs are
enabled. An attacker could use this to expose sensitive information
(kernel memory) or possibly cause undesired behaviors. (LP: #2023220)

Update instructions:

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

Ubuntu 23.04:
linux-image-6.2.0-1004-ibm 6.2.0-1004.4
linux-image-6.2.0-1006-azure 6.2.0-1006.6
linux-image-6.2.0-1006-oracle 6.2.0-1006.6
linux-image-6.2.0-1008-gcp 6.2.0-1008.8
linux-image-azure 6.2.0.1006.6
linux-image-gcp 6.2.0.1008.8
linux-image-ibm 6.2.0.1004.4
linux-image-oracle 6.2.0.1006.6

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-6220-1
https://launchpad.net/bugs/2023220
https://launchpad.net/bugs/2023577
CVE-2023-35788

Package Information:
https://launchpad.net/ubuntu/+source/linux-azure/6.2.0-1006.6
https://launchpad.net/ubuntu/+source/linux-gcp/6.2.0-1008.8
https://launchpad.net/ubuntu/+source/linux-ibm/6.2.0-1004.4
https://launchpad.net/ubuntu/+source/linux-oracle/6.2.0-1006.6