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Security Advisory

USN-6055-2: Ruby regression




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 18.04


USN-6055-1 fixed a vulnerability in Ruby. Unfortunately it introduced a regression. This update reverts the patches applied to CVE-2023-28755 in order to fix the regression pending further investigation. We apologize for the inconvenience. Original advisory details: It was discovered that Ruby incorrectly handled certain regular expressions. An attacker could possibly use this issue to cause a denial of service. (CVE-2023-28755) Update Instructions: Run `sudo pro fix USN-6055-2` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: libruby2.3 – 2.3.1-2~ubuntu16.04.16+esm6 ruby2.3 – 2.3.1-2~ubuntu16.04.16+esm6 ruby2.3-dev – 2.3.1-2~ubuntu16.04.16+esm6 ruby2.3-doc – 2.3.1-2~ubuntu16.04.16+esm6 ruby2.3-tcltk – 2.3.1-2~ubuntu16.04.16+esm6 Available with Ubuntu Pro (Infra-only):

CVEs contained in this USN include: CVE-2023-28755.

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • cflinuxfs3
    • All versions prior to 0.365.0
  • CF Deployment
    • All versions prior to 30.0.0


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 0.365.0 or greater
  • CF Deployment
    • Upgrade all versions to 30.0.0 or greater


2023-06-30: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR