1. Ubuntu Security Notices
  2. USN-7874-1

USN-7874-1: Linux kernel vulnerabilities

Publication date

19 November 2025

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

Details

Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered
that the Linux kernel contained insufficient branch predictor isolation
between a guest and a userspace hypervisor for certain processors. This
flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this
to expose sensitive information from the host OS. (CVE-2025-40300)

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:

  • HSI subsystem;
  • I3C subsystem;
  • SMB network file system;
  • Padata parallel execution mechanism;
  • Timer subsystem;
  • Networking core

Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered
that the Linux kernel contained insufficient branch predictor isolation
between a guest and a userspace hypervisor for certain processors. This
flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this
to expose sensitive information from the host OS. (CVE-2025-40300)

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:

  • HSI subsystem;
  • I3C subsystem;
  • SMB network file system;
  • Padata parallel execution mechanism;
  • Timer subsystem;
  • Networking core

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-5.4.0-1070-xilinx-zynqmp –  5.4.0-1070.74  
linux-image-5.4.0-1098-ibm –  5.4.0-1098.103  
linux-image-5.4.0-1135-raspi –  5.4.0-1135.148  
linux-image-5.4.0-1139-kvm –  5.4.0-1139.148  
linux-image-5.4.0-1150-oracle –  5.4.0-1150.160  
linux-image-5.4.0-1152-aws –  5.4.0-1152.162  
linux-image-5.4.0-1155-gcp –  5.4.0-1155.164  
linux-image-5.4.0-223-generic –  5.4.0-223.243  
linux-image-5.4.0-223-generic-lpae –  5.4.0-223.243  
linux-image-5.4.0-223-lowlatency –  5.4.0-223.243  
linux-image-aws-5.4 –  5.4.0.1152.149  
linux-image-aws-lts-20.04 –  5.4.0.1152.149  
linux-image-gcp-5.4 –  5.4.0.1155.157  
linux-image-gcp-lts-20.04 –  5.4.0.1155.157  
linux-image-generic –  5.4.0.223.215  
linux-image-generic-5.4 –  5.4.0.223.215  
linux-image-generic-lpae –  5.4.0.223.215  
linux-image-generic-lpae-5.4 –  5.4.0.223.215  
linux-image-ibm-5.4 –  5.4.0.1098.127  
linux-image-ibm-lts-20.04 –  5.4.0.1098.127  
linux-image-kvm –  5.4.0.1139.135  
linux-image-kvm-5.4 –  5.4.0.1139.135  
linux-image-lowlatency –  5.4.0.223.215  
linux-image-lowlatency-5.4 –  5.4.0.223.215  
linux-image-oem –  5.4.0.223.215  
linux-image-oem-osp1 –  5.4.0.223.215  
linux-image-oracle-5.4 –  5.4.0.1150.144  
linux-image-oracle-lts-20.04 –  5.4.0.1150.144  
linux-image-raspi –  5.4.0.1135.166  
linux-image-raspi-5.4 –  5.4.0.1135.166  
linux-image-raspi2 –  5.4.0.1135.166  
linux-image-virtual –  5.4.0.223.215  
linux-image-virtual-5.4 –  5.4.0.223.215  
linux-image-xilinx-zynqmp –  5.4.0.1070.70  
linux-image-xilinx-zynqmp-5.4 –  5.4.0.1070.70  
18.04 LTS bionic linux-image-5.4.0-1098-ibm –  5.4.0-1098.103~18.04.1  
linux-image-5.4.0-1135-raspi –  5.4.0-1135.148~18.04.1  
linux-image-5.4.0-1150-oracle –  5.4.0-1150.160~18.04.1  
linux-image-5.4.0-1152-aws –  5.4.0-1152.162~18.04.1  
linux-image-5.4.0-1155-gcp –  5.4.0-1155.164~18.04.1  
linux-image-5.4.0-223-generic –  5.4.0-223.243~18.04.1  
linux-image-5.4.0-223-lowlatency –  5.4.0-223.243~18.04.1  
linux-image-aws –  5.4.0.1152.162~18.04.1  
linux-image-aws-5.4 –  5.4.0.1152.162~18.04.1  
linux-image-gcp –  5.4.0.1155.164~18.04.1  
linux-image-gcp-5.4 –  5.4.0.1155.164~18.04.1  
linux-image-generic-5.4 –  5.4.0.223.243~18.04.1  
linux-image-generic-hwe-18.04 –  5.4.0.223.243~18.04.1  
linux-image-ibm –  5.4.0.1098.103~18.04.1  
linux-image-ibm-5.4 –  5.4.0.1098.103~18.04.1  
linux-image-lowlatency-5.4 –  5.4.0.223.243~18.04.1  
linux-image-lowlatency-hwe-18.04 –  5.4.0.223.243~18.04.1  
linux-image-oem –  5.4.0.223.243~18.04.1  
linux-image-oem-osp1 –  5.4.0.223.243~18.04.1  
linux-image-oracle –  5.4.0.1150.160~18.04.1  
linux-image-oracle-5.4 –  5.4.0.1150.160~18.04.1  
linux-image-raspi-5.4 –  5.4.0.1135.148~18.04.1  
linux-image-raspi-hwe-18.04 –  5.4.0.1135.148~18.04.1  
linux-image-snapdragon-5.4 –  5.4.0.223.243~18.04.1  
linux-image-snapdragon-hwe-18.04 –  5.4.0.223.243~18.04.1  
linux-image-virtual-5.4 –  5.4.0.223.243~18.04.1  
linux-image-virtual-hwe-18.04 –  5.4.0.223.243~18.04.1  

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References

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