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Security Advisory

USN-4040-1: Expat vulnerability

USN-4040-1: Expat vulnerability




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04


It was discovered that Expat incorrectly handled certain XML files. An attacker could possibly use this issue to cause a denial of service.

CVEs contained in this USN include: CVE-2018-20843

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • Cloud Foundry BOSH xenial-stemcells are vulnerable, including:
    • 315.x versions prior to 315.64
    • 250.x versions prior to 250.79
    • 170.x versions prior to 170.107
    • 97.x versions prior to 97.132
    • All other stemcells not listed.
  • All versions of Cloud Foundry cflinuxfs3 prior to 0.108.0


Users of affected products are strongly encouraged to follow one of the mitigations below:

  • The Cloud Foundry project recommends upgrading the following BOSH xenial-stemcells:
    • Upgrade 315.x versions to 315.64
    • Upgrade 250.x versions to 250.79
    • Upgrade 170.x versions to 170.107
    • Upgrade 97.x versions to 97.132
    • All other stemcells should be upgraded to the latest version available on
  • The Cloud Foundry project recommends that Cloud Foundry deployments run with cflinuxfs3 version 0.108.0 or later.


Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR