[USN-7758-3] Linux kernel (Real-time) vulnerability

[Giampaolo Fresi Roglia]

==========================================================================
Ubuntu Security Notice USN-7758-3
September 19, 2025

linux-realtime vulnerability
==========================================================================

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

- Ubuntu 24.04 LTS

Summary:

The system could be made to crash or run programs as an administrator.

Software Description:
- linux-realtime: Linux kernel for Real-time systems

Details:

It was discovered that the AF_UNIX socket garbage collection implementation
in Ubuntu Noble's 6.8 kernel did not properly handle out-of-band (OOB)
messages, leading to a use-after-free vulnerability. An attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code.

Update instructions:

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

Ubuntu 24.04 LTS
  linux-image-6.8.1-1033-realtime  6.8.1-1033.34
                                  Available with Ubuntu Pro
  linux-image-realtime            6.8.1-1033.34
                                  Available with Ubuntu Pro
  linux-image-realtime-6.8.1      6.8.1-1033.34
                                  Available with Ubuntu Pro

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-7758-3
  https://ubuntu.com/security/notices/USN-7758-2
  https://ubuntu.com/security/notices/USN-7758-1
  https://launchpad.net/bugs/2121515

Package Information:
  https://launchpad.net/ubuntu/+source/linux-realtime/6.8.1-1033.34

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