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Security Advisory

USN-4898-1: curl vulnerabilities




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04


Viktor Szakats discovered that curl did not strip off user credentials from referrer header fields. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2021-22876)

Mingtao Yang discovered that curl incorrectly handled session tickets when using an HTTPS proxy. A remote attacker in control of an HTTPS proxy could use this issue to bypass certificate checks and intercept communications. This issue only affected Ubuntu 20.04 LTS and Ubuntu 20.10. (CVE-2021-22890)

CVEs contained in this USN include: CVE-2021-22890, CVE-2021-22876.

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • cflinuxfs3
    • All versions prior to 0.233.0
  • Xenial Stemcells
    • 456.x versions prior to 456.158
    • 621.x versions prior to 621.123
    • All other stemcells not listed.
  • CF Deployment
    • All versions prior to 16.13.0


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

  • cflinuxfs3
    • Upgrade all versions to 0.233.0 or greater
  • Xenial Stemcells
    • Upgrade 456.x versions to 456.158 or greater
    • Upgrade 621.x versions to 621.123 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • Upgrade all versions to 16.13.0 or greater


2021-04-29: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR