==========================================================================
Ubuntu Security Notice USN-6343-1
September 06, 2023

linux-oem-6.1 vulnerabilities
==========================================================================

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

- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-oem-6.1: Linux kernel for OEM systems

Details:

It was discovered that the IPv6 implementation in the Linux kernel
contained a high rate of hash collisions in connection lookup table. A
remote attacker could use this to cause a denial of service (excessive CPU
consumption). (CVE-2023-1206)

Ross Lagerwall discovered that the Xen netback backend driver in the Linux
kernel did not properly handle certain unusual packets from a
paravirtualized network frontend, leading to a buffer overflow. An attacker
in a guest VM could use this to cause a denial of service (host system
crash) or possibly execute arbitrary code. (CVE-2023-34319)

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle L2CAP socket release, 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-2023-40283)

It was discovered that some network classifier implementations in the Linux
kernel contained use-after-free vulnerabilities. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2023-4128)

Andy Nguyen discovered that the KVM implementation for AMD processors in
the Linux kernel with Secure Encrypted Virtualization (SEV) contained a
race condition when accessing the GHCB page. A local attacker in a SEV
guest VM could possibly use this to cause a denial of service (host system
crash). (CVE-2023-4155)

It was discovered that the TUN/TAP driver in the Linux kernel did not
properly initialize socket data. A local attacker could use this to cause a
denial of service (system crash). (CVE-2023-4194)

Maxim Suhanov discovered that the exFAT file system implementation in the
Linux kernel did not properly check a file name length, leading to an out-
of-bounds write vulnerability. An attacker could use this to construct a
malicious exFAT image that, when mounted and operated on, could cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2023-4273)

Update instructions:

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

Ubuntu 22.04 LTS:
   linux-image-6.1.0-1021-oem      6.1.0-1021.21
   linux-image-oem-22.04c          6.1.0.1021.21

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-6343-1
   CVE-2023-1206, CVE-2023-34319, CVE-2023-40283, CVE-2023-4128,
   CVE-2023-4155, CVE-2023-4194, CVE-2023-4273

Package Information:
   https://launchpad.net/ubuntu/+source/linux-oem-6.1/6.1.0-1021.21