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

[USN-6321-1] Linux kernel vulnerabilities

==========================================================================
Ubuntu Security Notice USN-6321-1
August 30, 2023

linux-gcp, linux-starfive vulnerabilities
==========================================================================

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

Details:

Daniel Moghimi discovered that some Intel(R) Processors did not properly
clear microarchitectural state after speculative execution of various
instructions. A local unprivileged user could use this to obtain to
sensitive information. (CVE-2022-40982)

Tavis Ormandy discovered that some AMD processors did not properly handle
speculative execution of certain vector register instructions. A local
attacker could use this to expose sensitive information. (CVE-2023-20593)

It was discovered that the universal 32bit network packet classifier
implementation in the Linux kernel did not properly perform reference
counting in some situations, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2023-3609)

It was discovered that the netfilter subsystem in the Linux kernel did not
properly handle certain error conditions, leading to a use-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-3610)

It was discovered that the Quick Fair Queueing network scheduler
implementation in the Linux kernel contained an out-of-bounds write
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-3611)

It was discovered that the network packet classifier with
netfilter/firewall marks implementation in the Linux kernel did not
properly handle reference counting, leading to a use-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-3776)

Kevin Rich discovered that the netfilter subsystem in the Linux kernel did
not properly handle table rules flush in certain circumstances. A local
attacker could possibly use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2023-3777)

Kevin Rich discovered that the netfilter subsystem in the Linux kernel did
not properly handle rule additions to bound chains in certain
circumstances. A local attacker could possibly use this to cause a denial
of service (system crash) or execute arbitrary code. (CVE-2023-3995)

It was discovered that the netfilter subsystem in the Linux kernel did not
properly handle PIPAPO element removal, leading to a use-after-free
vulnerability. A local attacker could possibly use this to cause a denial
of service (system crash) or execute arbitrary code. (CVE-2023-4004)

Kevin Rich discovered that the netfilter subsystem in the Linux kernel did
not properly handle bound chain deactivation in certain circumstances. A
local attacker could possibly use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2023-4015)

Update instructions:

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

Ubuntu 23.04:
linux-image-6.2.0-1003-starfive 6.2.0-1003.3
linux-image-6.2.0-1012-gcp 6.2.0-1012.12
linux-image-gcp 6.2.0.1012.12
linux-image-starfive 6.2.0.1003.6

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-6321-1
CVE-2022-40982, CVE-2023-20593, CVE-2023-3609, CVE-2023-3610,
CVE-2023-3611, CVE-2023-3776, CVE-2023-3777, CVE-2023-3995,
CVE-2023-4004, CVE-2023-4015

Package Information:
https://launchpad.net/ubuntu/+source/linux-gcp/6.2.0-1012.12
https://launchpad.net/ubuntu/+source/linux-starfive/6.2.0-1003.3