1. Ubuntu Security Notices
  2. USN-8390-2

USN-8390-2: Linux kernel vulnerability

Publication date

17 June 2026

Overview

The system could be made to run programs as an administrator.

Releases

Packages

  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • linux-oracle - Linux kernel for Oracle Cloud systems

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.

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.

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
16.04 LTS xenial linux-image-4.15.0-1155-oracle –  4.15.0-1155.166~16.04.1  
linux-image-4.15.0-1186-gcp –  4.15.0-1186.203~16.04.1  
linux-image-4.15.0-1202-azure –  4.15.0-1202.217~16.04.1  
linux-image-4.15.0-251-generic –  4.15.0-251.263~16.04.1  
linux-image-4.15.0-251-lowlatency –  4.15.0-251.263~16.04.1  
linux-image-azure –  4.15.0.1202.217~16.04.1  
linux-image-gcp –  4.15.0.1186.203~16.04.1  
linux-image-generic-hwe-16.04 –  4.15.0.251.263~16.04.1  
linux-image-gke –  4.15.0.1186.203~16.04.1  
linux-image-lowlatency-hwe-16.04 –  4.15.0.251.263~16.04.1  
linux-image-oem –  4.15.0.251.263~16.04.1  
linux-image-oracle –  4.15.0.1155.166~16.04.1  
linux-image-virtual-hwe-16.04 –  4.15.0.251.263~16.04.1  

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References

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