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Security Advisory

USN-6485-1: Intel Microcode vulnerability




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04
  • Canonical Ubuntu 22.04


Benoit Morgan, Paul Grosen, Thais Moreira Hamasaki, Ke Sun, Alyssa Milburn, Hisham Shafi, Nir Shlomovich, Tavis Ormandy, Daniel Moghimi, Josh Eads, Salman Qazi, Alexandra Sandulescu, Andy Nguyen, Eduardo Vela, Doug Kwan, and Kostik Shtoyk discovered that some Intel(R) Processors did not properly handle certain sequences of processor instructions. A local attacker could possibly use this to cause a core hang (resulting in a denial of service), gain access to sensitive information or possibly escalate their privileges. Update Instructions: Run `sudo pro fix USN-6485-1` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: intel-microcode – 3.20231114.0ubuntu0.16.04.1+esm1 Available with Ubuntu Pro (Infra-only):

CVEs contained in this USN include: CVE-2023-23583.

Affected Cloud Foundry Products and Versions

Severity is high unless otherwise noted.

  • Jammy Stemcells
    • 1.x versions prior to 1.301
    • All other stemcells not listed.
  • CF Deployment
    • All versions with Jammy Stemcells prior to 1.301


Users of affected products are strongly encouraged to follow the mitigations below. The Cloud Foundry project recommends upgrading the following releases:

  • Jammy Stemcells
    • Upgrade 1.x versions to 1.301 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • For all versions, upgrade Jammy Stemcells to 1.301 or greater


2023-12-04: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR