1. Ubuntu Security Notices
  2. USN-7864-1

USN-7864-1: Linux kernel (GCP and GKE) vulnerabilities

Publication date

7 November 2025

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-6.8 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gke - Linux kernel for Google Container Engine (GKE) systems

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;
  • I2C subsystem;
  • Bluetooth subsystem;
  • Timer subsystem

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;
  • I2C subsystem;
  • Bluetooth subsystem;
  • Timer subsystem

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
24.04 LTS noble linux-image-6.8.0-1039-gke –  6.8.0-1039.44
linux-image-6.8.0-1039-gke-64k –  6.8.0-1039.44
linux-image-6.8.0-1043-gcp –  6.8.0-1043.46
linux-image-6.8.0-1043-gcp-64k –  6.8.0-1043.46
linux-image-gcp-6.8 –  6.8.0-1043.46
linux-image-gcp-64k-6.8 –  6.8.0-1043.46
linux-image-gcp-64k-lts-24.04 –  6.8.0-1043.46
linux-image-gcp-lts-24.04 –  6.8.0-1043.46
linux-image-gke –  6.8.0-1039.44
linux-image-gke-6.8 –  6.8.0-1039.44
linux-image-gke-64k –  6.8.0-1039.44
linux-image-gke-64k-6.8 –  6.8.0-1039.44
22.04 LTS jammy linux-image-6.8.0-1043-gcp –  6.8.0-1043.46~22.04.1
linux-image-6.8.0-1043-gcp-64k –  6.8.0-1043.46~22.04.1
linux-image-gcp –  6.8.0-1043.46~22.04.1
linux-image-gcp-6.8 –  6.8.0-1043.46~22.04.1
linux-image-gcp-64k –  6.8.0-1043.46~22.04.1
linux-image-gcp-64k-6.8 –  6.8.0-1043.46~22.04.1

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References

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