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Security Advisory

USN-6592-1: libssh vulnerabilities




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 22.04


It was discovered that libssh incorrectly handled the ProxyCommand and the ProxyJump features. A remote attacker could possibly use this issue to inject malicious code into the command of the features mentioned through the hostname parameter. (CVE-2023-6004) It was discovered that libssh incorrectly handled return codes when performing message digest operations. A remote attacker could possibly use this issue to cause libssh to crash, obtain sensitive information, or execute arbitrary code. (CVE-2023-6918) Update Instructions: Run `sudo pro fix USN-6592-1` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: libssh-gcrypt-dev – 0.9.3-2ubuntu2.5 libssh-4 – 0.9.3-2ubuntu2.5 libssh-gcrypt-4 – 0.9.3-2ubuntu2.5 libssh-dev – 0.9.3-2ubuntu2.5 libssh-doc – 0.9.3-2ubuntu2.5 No subscription required

CVEs contained in this USN include: CVE-2023-6004, CVE-2023-6918.

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • cflinuxfs4
    • All versions prior to 1.67.0
  • Jammy Stemcells
    • 1.x versions prior to 1.351
    • All other stemcells not listed.
  • CF Deployment
    • All versions with Jammy Stemcells prior to 1.351


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

The Cloud Foundry project recommends upgrading the following releases:

  • cflinuxfs4
    • Upgrade all versions to 1.67.0 or greater
  • Jammy Stemcells
    • Upgrade 1.x versions to 1.351 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • For all versions, upgrade Jammy Stemcells to 1.351 or greater


2024-02-29: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR