1. Ubuntu Security Notices
  2. USN-7853-1

USN-7853-1: Linux kernel vulnerabilities

Publication date

30 October 2025

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-4.15 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • linux-oracle - Linux kernel for Oracle Cloud 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:

  • DMA engine subsystem;
  • GPU drivers;
  • HSI subsystem;
  • Ethernet team driver;
  • Ext4 file system;
  • Timer subsystem;
  • DCCP (Datagram Congestion Control Protocol);
  • IPv6 networking;
  • NET/ROM layer;
  • SCTP protocol;
  • USB sound devices

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:

  • DMA engine subsystem;
  • GPU drivers;
  • HSI subsystem;
  • Ethernet team driver;
  • Ext4 file system;
  • Timer subsystem;
  • DCCP (Datagram Congestion Control Protocol);
  • IPv6 networking;
  • NET/ROM layer;
  • SCTP protocol;
  • USB sound devices

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
18.04 LTS bionic linux-image-4.15.0-1148-oracle –  4.15.0-1148.159  
linux-image-4.15.0-1179-gcp –  4.15.0-1179.196  
linux-image-4.15.0-1186-aws –  4.15.0-1186.199  
linux-image-4.15.0-243-generic –  4.15.0-243.255  
linux-image-4.15.0-243-lowlatency –  4.15.0-243.255  
linux-image-aws-4.15 –  4.15.0.1186.184  
linux-image-aws-lts-18.04 –  4.15.0.1186.184  
linux-image-gcp-4.15 –  4.15.0.1179.192  
linux-image-gcp-lts-18.04 –  4.15.0.1179.192  
linux-image-generic –  4.15.0.243.227  
linux-image-lowlatency –  4.15.0.243.227  
linux-image-oracle-4.15 –  4.15.0.1148.153  
linux-image-oracle-lts-18.04 –  4.15.0.1148.153  
linux-image-virtual –  4.15.0.243.227  
16.04 LTS xenial linux-image-4.15.0-1179-gcp –  4.15.0-1179.196~16.04.1  
linux-image-4.15.0-1186-aws –  4.15.0-1186.199~16.04.1  
linux-image-4.15.0-243-generic –  4.15.0-243.255~16.04.1  
linux-image-4.15.0-243-lowlatency –  4.15.0-243.255~16.04.1  
linux-image-aws-hwe –  4.15.0.1186.199~16.04.1  
linux-image-gcp –  4.15.0.1179.196~16.04.1  
linux-image-generic-hwe-16.04 –  4.15.0.243.255~16.04.1  
linux-image-gke –  4.15.0.1179.196~16.04.1  
linux-image-lowlatency-hwe-16.04 –  4.15.0.243.255~16.04.1  
linux-image-oem –  4.15.0.243.255~16.04.1  
linux-image-virtual-hwe-16.04 –  4.15.0.243.255~16.04.1  

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References

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