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Ubuntu 18.04 LTS Linux Kernel Privilege Escalation Vulnerability USN-8281-2

ubuntu
Calendar Grey May 22, 2026
Dist Ubuntu Esm H88
Critical updates for Ubuntu 18.04 LTS involve security fixes in the Linux kernel to protect against local attacks.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-azure-4.15: Linux kernel for Microsoft Azure Cloud systems

- linux-azure-fips: Linux kernel for Microsoft Azure Cloud systems with FIPS

Details:

It was discovered that the Linux kernel algif_aead module did not properly

handle in-place cryptographic operations. This flaw is known as Copy Fail.

A local attacker could use this to escalate privileges, or possibly escape

a container. (CVE-2026-31431)

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:

- Cryptographic API;

- Packet sockets;

(CVE-2026-31504, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078)

Topics%20covered

Topics Covered

security advisory Ubuntu fips exploits Linux kernel escalation

Update Instructions

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

Ubuntu 18.04 LTS
   linux-image-4.15.0-1201-azure   4.15.0-1201.216
                                   Available with Ubuntu Pro
   linux-image-4.15.0-2110-azure-fips  4.15.0-2110.116
                                   Available with Ubuntu Pro
   linux-image-azure-4.15          4.15.0.1201.169
                                   Available with Ubuntu Pro
   linux-image-azure-fips          4.15.0.2110.106
                                   Available with Ubuntu Pro
   linux-image-azure-fips-4.15     4.15.0.2110.106
                                   Available with Ubuntu Pro
   linux-image-azure-lts-18.04     4.15.0.1201.169
                                   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-8281-2

https://ubuntu.com/security/notices/USN-8281-1

CVE-2026-31431, CVE-2026-31504, CVE-2026-43033, CVE-2026-43077,

CVE-2026-43078

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8281-2

Topics%20covered

Topics Covered

security advisory Ubuntu fips exploits Linux kernel escalation

Package Information

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