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Security Advisory

USN-4001-1: libseccomp vulnerability

USN-4001-1: libseccomp vulnerability




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04


Jann Horn discovered that libseccomp did not correctly generate 64-bit syscall argument comparisons with arithmetic operators (LT, GT, LE, GE). An attacker could use this to bypass intended access restrictions for argument-filtered system calls.

CVEs contained in this USN include: CVE-2019-9893

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 315.36
    • 250.x versions prior to 250.58
    • 170.x versions prior to 170.78
    • 97.x versions prior to 97.108
    • All other stemcells not listed.
  • All versions of Cloud Foundry cflinuxfs3 prior to 0.94.0


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 315.36
    • Upgrade 250.x versions to 250.58
    • Upgrade 170.x versions to 170.78
    • Upgrade 97.x versions to 97.108
    • 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 0.94.0 or later.


Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR