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Ubuntu 25.10 USN-8245-1 Linux-Azure Critical Security EntrySign Threat

ubuntu
Calendar Grey May 7, 2026
Dist Ubuntu Esm H88
Multiple security flaws fixed in Ubuntu Linux kernel affecting Azure cloud systems. Update immediately for protection.
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-6.17: Linux kernel for Microsoft Azure cloud systems

- linux-oem-6.17: Linux kernel for OEM systems

Details:

Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo

Rizzo discovered that some AMD Zen processors did not properly verify the

signature of CPU microcode. This flaw is known as EntrySign. A privileged

attacker could possibly use this issue to cause load malicious CPU

microcode causing loss of integrity and confidentiality. (CVE-2024-36347)

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:

- MIPS architecture;

- PowerPC architecture;

- User-Mode Linux (UML);

- x86 architecture;

- Block layer subsystem;

- Cryptographic API;

- ACPI drivers;

- Ublk userspace b...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory critical Ubuntu kernel linux-azure entrysign

Update Instructions

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

Ubuntu 25.10
  linux-image-6.17.0-1013-azure   6.17.0-1013.13
  linux-image-azure               6.17.0-1013.13
  linux-image-azure-6.17          6.17.0-1013.13

Ubuntu 24.04 LTS
  linux-image-6.17.0-1013-azure   6.17.0-1013.13~24.04.1
  linux-image-6.17.0-1020-oem     6.17.0-1020.20
  linux-image-azure               6.17.0-1013.13~24.04.1
  linux-image-azure-6.17          6.17.0-1013.13~24.04.1
  linux-image-oem-24.04           6.17.0-1020.20
  linux-image-oem-24.04a          6.17.0-1020.20
  linux-image-oem-24.04b          6.17.0-1020.20
  linux-image-oem-24.04c          6.17.0-1020.20
  linux-image-oem-24.04d          6.17.0-1020.20
  linux-image-oem-6.17            6.17.0-1020.20

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-8245-1

CVE-2024-36347, CVE-2025-68351, CVE-2025-68353, CVE-2025-68365,

CVE-2025-68368, CVE-2025-68725, CVE-2025-68736, CVE-2025-68745,

CVE-2025-68767, CVE-2025-68768, CVE-2025-68769, CVE-2025-68770,

CVE-2025-68771, CVE-2025-68772, CVE-2025-68773, CVE-2025-68774,

CVE-2025-68775, CVE-2025-68776, CVE-2025-68777, CVE-2025-68778,

CVE-2025-68780, CVE-2025-68781, CVE-2025-68782, CVE-2025-68783,

CVE-2025-68784, CVE-2025-68785, CVE-2025-68786, CVE-2025-68787,

CVE-2025-68788, CVE-2025-68791, CVE-2025-68792, CVE-2025-68793,

CVE-2025-68794, CVE-2025-68795, CVE-2025-68796, CVE-2025-68797,

CVE-2025-68798, CVE-2025-68799, CVE-2025-68800, CVE-2025-68801,

CVE-2025-68802, CVE-2025-68803, CVE-2025-68804, CVE-2025-68805,

CVE-2025-68806, CVE-2025-68807, CVE-2025-68808, CVE-2025-68809,

CVE-2025-68810, CVE-2025-68811, CVE-2025-68813, CVE-2025-68814,

CVE-2025-68815, CVE-2025-68816, CVE-2025-68817, CVE-2025-68818,

CVE-2025-68819, CVE-2025-68820, CVE-2025-68821, CVE-2025-68822,

CVE-2025-68823, CVE-2025-71064, CVE-2025-71065, CVE-2025-71066,

CVE-2025-71067, CVE-2025-71068, CVE-2025-71069, CVE-2025-71070,

CVE-2025-71071, CVE-2025-71072, CVE-2025-71073, CVE-2025-71075,

CVE-2025-71076, CVE-2025-71077, CVE-2025-71078, CVE-2025-71079,

CVE-2025-71081, CVE-2025-71082, CVE-2025-71083, CVE-2025-71084,

CVE-2025-71085, CVE-2025-71086, CVE-2025-71087, CVE-2025-71089,

CVE-2025-71091, CVE-2025-71093, CVE-2025-71094, CVE-2025-71095,

CVE-2025-71096, CVE-2025-71097, CVE-2025-71098, CVE-2025-71099,

CVE-2025-71100, CVE-2025-71101, CVE-2025-71102, CVE-2025-71104,

CVE-2025-71105, CVE-2025-71107, CVE-2025-71108, CVE-2025-71109,

CVE-2025-71111, CVE-2025-71112, CVE-2025-71113, CVE-2025-71114,

CVE-2025-71115, CVE-2025-71116, CVE-2025-71117, CVE-2025-71118,

CVE-2025-71119, CVE-2025-71120, CVE-2025-71121, CVE-2025-71122,

CVE-2025-71123, CVE-2025-71124, CVE-2025-71125, CVE-2025-71126,

CVE-2025-71130, CVE-2025-71131, CVE-2025-71132, CVE-2025-71133,

CVE-2025-71135, CVE-2025-71136, CVE-2025-71137, CVE-2025-71138,

CVE-2025-71140, CVE-2025-71143, CVE-2025-71146, CVE-2025-71147,

CVE-2025-71148, CVE-2025-71149, CVE-2025-71150, CVE-2025-71151,

CVE-2025-71153, CVE-2025-71154, CVE-2025-71156, CVE-2025-71157,

CVE-2026-23091, CVE-2026-23112, CVE-2026-23209, CVE-2026-23231

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8245-1

Topics%20covered

Topics Covered

security advisory critical Ubuntu kernel linux-azure entrysign

Package Information

https://launchpad.net/ubuntu/+source/linux-azure/6.17.0-1013.13
https://launchpad.net/ubuntu/+source/linux-azure-6.17/6.17.0-1013.13~24.04.1
https://launchpad.net/ubuntu/+source/linux-oem-6.17/6.17.0-1020.20

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