==========================================================================
Ubuntu Security Notice USN-6072-1
May 10, 2023

linux-oem-6.0 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-6.0: Linux kernel for OEM systems

Details:

It was discovered that the Traffic-Control Index (TCINDEX) implementation
in the Linux kernel did not properly perform filter deactivation in some
situations. A local attacker could possibly use this to gain elevated
privileges. Please note that with the fix for this CVE, kernel support for
the TCINDEX classifier has been removed. (CVE-2023-1829)

Lin Ma discovered a race condition in the io_uring subsystem in the Linux
kernel, leading to a null pointer dereference vulnerability. A local
attacker could use this to cause a denial of service (system crash).
(CVE-2023-0468)

It was discovered that the OverlayFS implementation in the Linux kernel did
not properly handle copy up operation in some conditions. A local attacker
could possibly use this to gain elevated privileges. (CVE-2023-0386)

It was discovered that a race condition existed in the Xen transport layer
implementation for the 9P file system protocol in the Linux kernel, leading
to a use-after-free vulnerability. A local attacker could use this to cause
a denial of service (guest crash) or expose sensitive information (guest
kernel memory). (CVE-2023-1859)

Kyle Zeng discovered that the ATM VC queuing discipline implementation in
the Linux kernel contained a type confusion vulnerability in some
situations. An attacker could use this to cause a denial of service (system
crash). (CVE-2023-23455)

Lianhui Tang discovered that the MPLS implementation in the Linux kernel
did not properly handle certain sysctl allocation failure conditions,
leading to a double-free vulnerability. An attacker could use this to cause
a denial of service or possibly execute arbitrary code. (CVE-2023-26545)

Update instructions:

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

Ubuntu 22.04 LTS:
   linux-image-6.0.0-1015-oem      6.0.0-1015.15
   linux-image-oem-22.04b          6.0.0.1015.15

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-6072-1
   CVE-2023-0386, CVE-2023-0468, CVE-2023-1829, CVE-2023-1859,
   CVE-2023-23455, CVE-2023-26545

Package Information:
   https://launchpad.net/ubuntu/+source/linux-oem-6.0/6.0.0-1015.15