==========================================================================
Ubuntu Security Notice USN-8391-1
June 04, 2026

linux-raspi, linux-raspi-5.4 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-raspi: Linux kernel for Raspberry Pi systems
- linux-raspi-5.4: Linux kernel for Raspberry Pi systems

Details:

It was discovered that the Linux kernel algif_aead module did not properly
handle in-place cryptographic operations. This flaw is known as Copy Fail.
A local attacker could use this to escalate privileges, or possibly escape
a container. (CVE-2026-31431)

It was discovered that the Linux kernel did not properly handle shared page
fragments during socket buffer operations, collectively known as Dirty
Frag. A logic flaw existed in the XFRM ESP-in-TCP subsystem and in the
RxRPC networking subsystem when processing paged fragments. A local
attacker could use this to escalate privileges, or possibly escape a
container. (CVE-2026-43284, CVE-2026-43500)


Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
   - Cryptographic API;
   - Network drivers;
   - NVME drivers;
   - IPv4 networking;
   - Packet sockets;
   - RDS protocol;
   - TLS protocol;
(CVE-2024-50304, CVE-2026-23112, CVE-2026-23209, CVE-2026-31504,
CVE-2026-31533, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078,
CVE-2026-43494, CVE-2026-46028)

Update instructions:

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

Ubuntu 20.04 LTS
   linux-image-5.4.0-1143-raspi    5.4.0-1143.156
                                   Available with Ubuntu Pro
   linux-image-raspi               5.4.0.1143.174
                                   Available with Ubuntu Pro
   linux-image-raspi-5.4           5.4.0.1143.174
                                   Available with Ubuntu Pro
   linux-image-raspi2              5.4.0.1143.174
                                   Available with Ubuntu Pro

Ubuntu 18.04 LTS
   linux-image-5.4.0-1143-raspi    5.4.0-1143.156~18.04.1
                                   Available with Ubuntu Pro
   linux-image-raspi-5.4           5.4.0.1143.156~18.04.1
                                   Available with Ubuntu Pro
   linux-image-raspi-hwe-18.04     5.4.0.1143.156~18.04.1
                                   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-8391-1
   CVE-2024-50304, CVE-2026-23112, CVE-2026-23209, CVE-2026-31431,
   CVE-2026-31504, CVE-2026-31533, CVE-2026-43033, CVE-2026-43077,
   CVE-2026-43078, CVE-2026-43284, CVE-2026-43494, CVE-2026-43500,
   CVE-2026-46028