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Ubuntu 24.04 LTS: USN-7935-1 Important Linux Kernel Issues CVE-2025-40300

ubuntu
Calendar Grey December 15, 2025
Dist Ubuntu Esm H88
Several security issues in the Linux kernel for Ubuntu affect cloud systems, requiring urgent updates for security.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

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

- linux-azure-6.8: Linux kernel for Microsoft Azure 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:

- Cryptographic API;

- HSI subsystem;

- Media drivers;

- Network drivers;

- Bluetooth subsystem;

- Timer subsystem;

- Memory management;

- Appletalk network protocol;

- Netfilter;

- TLS protocol;

(CVE-20...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory threat Ubuntu important cloud linux-azure

Update Instructions

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

Ubuntu 24.04 LTS
   linux-image-6.8.0-1044-azure    6.8.0-1044.50
   linux-image-azure-6.8           6.8.0-1044.50
   linux-image-azure-lts-24.04     6.8.0-1044.50

Ubuntu 22.04 LTS
   linux-image-6.8.0-1044-azure    6.8.0-1044.50~22.04.1
   linux-image-azure               6.8.0-1044.50~22.04.1
   linux-image-azure-6.8           6.8.0-1044.50~22.04.1

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-7935-1

CVE-2025-21729, CVE-2025-37838, CVE-2025-37958, CVE-2025-38118,

CVE-2025-38227, CVE-2025-38352, CVE-2025-38616, CVE-2025-38666,

CVE-2025-38678, CVE-2025-39964, CVE-2025-39993, CVE-2025-40018,

CVE-2025-40300

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-7935-1

Topics%20covered

Topics Covered

security advisory threat Ubuntu important cloud linux-azure

Package Information

https://launchpad.net/ubuntu/+source/linux-azure/6.8.0-1044.50
https://launchpad.net/ubuntu/+source/linux-azure-6.8/6.8.0-1044.50~22.04.1

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