USN-4182-3: Intel Microcode regression

4 December 2019

intel-microcode regression

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 19.10
  • Ubuntu 19.04
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS


USN-4182-1 introduced a regression in the Intel Microcode for some Skylake processors.

Software Description

  • intel-microcode - Processor microcode for Intel CPUs


USN-4182-1 provided updated Intel Processor Microcode. A regression was discovered that caused some Skylake processors to hang after a warm reboot. This update reverts the microcode for that specific processor family.

We apologize for the inconvenience.

Original advisory details:

Stephan van Schaik, Alyssa Milburn, Sebastian Ă–sterlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida, Giorgi Maisuradze, Moritz Lipp, Michael Schwarz, Daniel Gruss, and Jo Van Bulck discovered that Intel processors using Transactional Synchronization Extensions (TSX) could expose memory contents previously stored in microarchitectural buffers to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2019-11135)

It was discovered that certain Intel Xeon processors did not properly restrict access to a voltage modulation interface. A local privileged attacker could use this to cause a denial of service (system crash). (CVE-2019-11139)

Update instructions

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

Ubuntu 19.10
intel-microcode - 3.20191115.1ubuntu0.19.10.2
Ubuntu 19.04
intel-microcode - 3.20191115.1ubuntu0.19.04.2
Ubuntu 18.04 LTS
intel-microcode - 3.20191115.1ubuntu0.18.04.2
Ubuntu 16.04 LTS
intel-microcode - 3.20191115.1ubuntu0.16.04.2

To update your system, please follow these instructions:

After a standard system update you need to reboot your computer.