1. Ubuntu Security Notices
  2. USN-8615-1

USN-8615-1: Linux kernel vulnerabilities

Publication date

28 July 2026

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

Details

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;
  • RxRPC session...

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;
  • 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-5.4.0-1065-iot –  5.4.0-1065.68  
linux-image-5.4.0-1079-xilinx-zynqmp –  5.4.0-1079.83  
linux-image-5.4.0-1120-bluefield –  5.4.0-1120.127  
linux-image-5.4.0-1135-fips –  5.4.0-1135.145  
linux-image-5.4.0-1159-oracle –  5.4.0-1159.169  
linux-image-5.4.0-1161-aws –  5.4.0-1161.172  
linux-image-5.4.0-1161-aws-fips –  5.4.0-1161.172+fips1  
linux-image-5.4.0-1164-gcp –  5.4.0-1164.173  
linux-image-5.4.0-1164-gcp-fips –  5.4.0-1164.173+fips1  
linux-image-5.4.0-1166-azure –  5.4.0-1166.172  
linux-image-5.4.0-1166-azure-fips –  5.4.0-1166.172+fips1  
linux-image-5.4.0-233-generic –  5.4.0-233.253  
linux-image-5.4.0-233-generic-lpae –  5.4.0-233.253  
linux-image-5.4.0-233-lowlatency –  5.4.0-233.253  
linux-image-aws-5.4 –  5.4.0.1161.159  
linux-image-aws-fips –  5.4.0.1161.108  
linux-image-aws-fips-5.4 –  5.4.0.1161.108  
linux-image-aws-lts-20.04 –  5.4.0.1161.159  
linux-image-azure-5.4 –  5.4.0.1166.158  
linux-image-azure-fips –  5.4.0.1166.102  
linux-image-azure-fips-5.4 –  5.4.0.1166.102  
linux-image-azure-lts-20.04 –  5.4.0.1166.158  
linux-image-bluefield –  5.4.0.1120.116  
linux-image-bluefield-5.4 –  5.4.0.1120.116  
linux-image-fips –  5.4.0.1135.132  
linux-image-fips-5.4 –  5.4.0.1135.132  
linux-image-gcp-5.4 –  5.4.0.1164.166  
linux-image-gcp-fips –  5.4.0.1164.106  
linux-image-gcp-fips-5.4 –  5.4.0.1164.106  
linux-image-gcp-lts-20.04 –  5.4.0.1164.166  
linux-image-generic –  5.4.0.233.225  
linux-image-generic-5.4 –  5.4.0.233.225  
linux-image-generic-lpae –  5.4.0.233.225  
linux-image-generic-lpae-5.4 –  5.4.0.233.225  
linux-image-lowlatency –  5.4.0.233.225  
linux-image-lowlatency-5.4 –  5.4.0.233.225  
linux-image-oem –  5.4.0.233.225  
linux-image-oem-osp1 –  5.4.0.233.225  
linux-image-oracle-5.4 –  5.4.0.1159.153  
linux-image-oracle-lts-20.04 –  5.4.0.1159.153  
linux-image-virtual –  5.4.0.233.225  
linux-image-virtual-5.4 –  5.4.0.233.225  
linux-image-xilinx-zynqmp –  5.4.0.1079.79  
linux-image-xilinx-zynqmp-5.4 –  5.4.0.1079.79  
18.04 LTS bionic linux-image-5.4.0-1159-oracle –  5.4.0-1159.169~18.04.1  
linux-image-5.4.0-1161-aws –  5.4.0-1161.172~18.04.1  
linux-image-5.4.0-1164-gcp –  5.4.0-1164.173~18.04.1  
linux-image-5.4.0-1166-azure –  5.4.0-1166.172~18.04.1  
linux-image-5.4.0-233-generic –  5.4.0-233.253~18.04.1  
linux-image-5.4.0-233-lowlatency –  5.4.0-233.253~18.04.1  
linux-image-aws –  5.4.0.1161.172~18.04.1  
linux-image-aws-5.4 –  5.4.0.1161.172~18.04.1  
linux-image-azure –  5.4.0.1166.172~18.04.1  
linux-image-azure-5.4 –  5.4.0.1166.172~18.04.1  
linux-image-gcp –  5.4.0.1164.173~18.04.1  
linux-image-gcp-5.4 –  5.4.0.1164.173~18.04.1  
linux-image-generic-5.4 –  5.4.0.233.253~18.04.1  
linux-image-generic-hwe-18.04 –  5.4.0.233.253~18.04.1  
linux-image-lowlatency-5.4 –  5.4.0.233.253~18.04.1  
linux-image-lowlatency-hwe-18.04 –  5.4.0.233.253~18.04.1  
linux-image-oem –  5.4.0.233.253~18.04.1  
linux-image-oem-osp1 –  5.4.0.233.253~18.04.1  
linux-image-oracle –  5.4.0.1159.169~18.04.1  
linux-image-oracle-5.4 –  5.4.0.1159.169~18.04.1  
linux-image-snapdragon-5.4 –  5.4.0.233.253~18.04.1  
linux-image-snapdragon-hwe-18.04 –  5.4.0.233.253~18.04.1  
linux-image-virtual-5.4 –  5.4.0.233.253~18.04.1  
linux-image-virtual-hwe-18.04 –  5.4.0.233.253~18.04.1  

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References

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