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Ubuntu 16.04 LTS Linux kernel Privilege Escalation Vulnern USN-8548-1

ubuntu
Calendar Grey July 15, 2026
Dist Ubuntu Esm H88
Security update for Ubuntu addresses several critical flaws in the Linux kernel affecting multiple versions and subsystems.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-fips: Linux kernel with FIPS

- linux-aws: Linux kernel for Amazon Web Services (AWS) systems

- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP

subsystem in the Linux kernel when handling socket buffer fragments. This

flaw is known as Fragnesia. A local attacker could use this to escalate

privileges, or possibly escape a container. (CVE-2026-43503)

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:

- SCSI subsystem;

- Thermal drivers;

- USB over IP driver;

- File systems infrastructure;

- Ext4 file system;

- Network file system (NFS) server daemon;

- SMB network file system;

- Tracing infrastructure;

- B.A.T.M.A.N. meshing protocol;

- Ceph Core lib...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory privilege escalation Ubuntu important local access logic flaw

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 LTS
  linux-image-4.4.0-1126-fips     4.4.0-1126.133
                                  Available with Ubuntu Pro
  linux-image-fips                4.4.0.1126.128
                                  Available with Ubuntu Pro

Ubuntu 14.04 LTS
  linux-image-4.4.0-1156-aws      4.4.0-1156.162
                                  Available with Ubuntu Pro
  linux-image-4.4.0-283-generic   4.4.0-283.317~14.04.1
                                  Available with Ubuntu Pro
  linux-image-4.4.0-283-lowlatency  4.4.0-283.317~14.04.1
                                  Available with Ubuntu Pro
  linux-image-aws                 4.4.0.1156.153
                                  Available with Ubuntu Pro
  linux-image-generic-lts-xenial  4.4.0.283.317~14.04.1
                                  Available with Ubuntu Pro
  linux-image-lowlatency-lts-xenial  4.4.0.283.317~14.04.1
                                  Available with Ubuntu Pro
  linux-image-virtual-lts-xenial  4.4.0.283.317~14.04.1
                                  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-8548-1

CVE-2021-47117, CVE-2021-47202, CVE-2023-52646, CVE-2024-56643,

CVE-2026-23455, CVE-2026-31402, CVE-2026-31607, CVE-2026-31637,

CVE-2026-31659, CVE-2026-31685, CVE-2026-43011, CVE-2026-43037,

CVE-2026-43038, CVE-2026-43383, CVE-2026-43407, CVE-2026-43414,

CVE-2026-43503, CVE-2026-45988, CVE-2026-46119, CVE-2026-46243

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8548-1

Topics%20covered

Topics Covered

security advisory privilege escalation Ubuntu important local access logic flaw

Package Information

https://launchpad.net/ubuntu/+source/linux-fips/4.4.0-1126.133

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