1. Ubuntu Security Notices
  2. USN-8616-1

USN-8616-1: Linux kernel (IBM) vulnerabilities

Publication date

28 July 2026

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

Details

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)

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP
subsystem in the Linux kernel when handling socket buffer fragments. This
flaw is known as Fragnesia. A local attacker could use this to escalate
privileges, or possibly escape a container. (CVE-2026-43503)

Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects...

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)

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP
subsystem in the Linux kernel when handling socket buffer fragments. This
flaw is known as Fragnesia. A local attacker could use this to escalate
privileges, or possibly escape a container. (CVE-2026-43503)

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:

  • InfiniBand drivers;
  • STMicroelectronics network drivers;
  • NVME drivers;
  • SCSI subsystem;
  • USB over IP driver;
  • Network file system (NFS) server daemon;
  • SMB network file system;
  • Tracing infrastructure;
  • B.A.T.M.A.N. meshing protocol;
  • Ethernet bridge;
  • Ceph Core library;
  • IPv4 networking;
  • IPv6 networking;
  • Netfilter;
  • RDS protocol;
  • RxRPC session sockets;
  • X.25 network layer

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
20.04 LTS focal linux-image-5.4.0-1107-ibm –  5.4.0-1107.112  
linux-image-ibm-5.4 –  5.4.0.1107.136  
linux-image-ibm-lts-20.04 –  5.4.0.1107.136  
18.04 LTS bionic linux-image-5.4.0-1107-ibm –  5.4.0-1107.112~18.04.1  
linux-image-ibm –  5.4.0.1107.112~18.04.1  
linux-image-ibm-5.4 –  5.4.0.1107.112~18.04.1  

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References

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