Ubuntu: Intel Microcode Critical Escalation Threat USN-7866-1

ubuntu

November 11, 2025

Several security issues were fixed in Intel Microcode.

Summary

Several security issues were fixed in Intel Microcode.

Software Description:

- intel-microcode: Processor microcode for Intel CPUs

Details:

Barak Gross discovered that some Intel® Xeon® processors with SGX enabled

did not properly handle buffer restrictions. A local authenticated user

could potentially use this issue to escalate their privileges.

(CVE-2025-20053)

Avinash Maddy discovered that some Intel® processors did not properly

isolate or compartmentalize the stream cache mechanisms. A local

authenticated user could potentially use this issue to escalate their

privileges. (CVE-2025-20109)

Joseph Nuzman discovered that some Intel® Xeon® processors did not properly

manage references to active allocate resources. A local authenticated user

could potentially use this issue to cause a denial of service (system

crash). (CVE-2025-21090)

It was discovered that some Intel® Xeon® 6 processors did not properly

provide sufficient granularity of access control in the out of band

...

Read the Full Advisory

Topics Covered

security advisory buffer overflow critical Ubuntu escalation microcode

Update Instructions

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

Ubuntu 25.10
  intel-microcode                 3.20250812.0ubuntu0.25.10.1

Ubuntu 25.04
  intel-microcode                 3.20250812.0ubuntu0.25.04.1

Ubuntu 24.04 LTS
  intel-microcode                 3.20250812.0ubuntu0.24.04.1

Ubuntu 22.04 LTS
  intel-microcode                 3.20250812.0ubuntu0.22.04.1

Ubuntu 20.04 LTS
  intel-microcode                 3.20250812.0ubuntu0.20.04.1+esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  intel-microcode                 3.20250812.0ubuntu0.18.04.1+esm1
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  intel-microcode                 3.20250812.0ubuntu0.16.04.1+esm1
                                  Available with Ubuntu Pro

After a standard system update you need to reboot your computer to make all
the necessary changes.