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Ubuntu 16.04 LTS Important Linux Kernel Local Escalation USN-8390-2

ubuntu
Calendar Grey June 17, 2026
Dist Ubuntu Esm H88
Ubuntu 16.04 LTS has a critical issue allowing local programs to gain administrative access through socket operations.
The system could be made to run programs as an administrator.

Summary

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 16.04 LTS Summary: The system could be made to run programs as an administrator. Software Description: - 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.

Topics%20covered

Topics Covered

security advisory local privilege escalation Ubuntu important Linux kernel socket operation

Update Instructions

The problem can be corrected by updating your system to the following package versions: Ubuntu 16.04 LTS linux-image-4.15.0-1155-oracle 4.15.0-1155.166~16.04.1 Available with Ubuntu Pro linux-image-4.15.0-1186-gcp 4.15.0-1186.203~16.04.1 Available with Ubuntu Pro linux-image-4.15.0-1202-azure 4.15.0-1202.217~16.04.1 Available with Ubuntu Pro linux-image-4.15.0-251-generic 4.15.0-251.263~16.04.1 Available with Ubuntu Pro linux-image-4.15.0-251-lowlatency 4.15.0-251.263~16.04.1 Available with Ubuntu Pro linux-image-azure 4.15.0.1202.217~16.04.1 Available with Ubuntu Pro linux-image-gcp 4.15.0.1186.203~16.04.1 Available with Ubuntu Pro linux-image-generic-hwe-16.04 4.15.0.251.263~16.04.1 Available with Ubuntu Pro linux-image-gke 4.15.0.1186.203~16.04.1 Available with Ubuntu Pro linux-image-lowlatency-hwe-16.04 4.15.0.251.263~16.04.1 Available with Ubuntu Pro linux-image-oem 4.15.0.251.263~16.04.1 Available with Ubuntu Pro linux-image-oracle 4.15.0.1155.166~16.04.1 Available with Ubuntu Pro linux-image-virtual-hwe-16.04 4.15.0.251.263~16.04.1 Available with Ubuntu Pro After a standard system update you need to reboot your computer to make all the necessary changes. 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.

References

https://ubuntu.com/security/notices/USN-8390-2

https://ubuntu.com/security/notices/USN-8390-1

CVE-2026-43284

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8390-2

Topics%20covered

Topics Covered

security advisory local privilege escalation Ubuntu important Linux kernel socket operation

Package Information

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