Cloud Foundry Logo
blog single gear
Security Advisory

USN-6168-2: libx11 vulnerability




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04


USN-6168-1 fixed a vulnerability in libx11. This update provides the corresponding update for Ubuntu 14.04 ESM, Ubuntu 16.04 ESM, and Ubuntu 18.04 ESM. Original advisory details: Gregory James Duck discovered that libx11 incorrectly handled certain Request, Event, or Error IDs. If a user were tricked into connecting to a malicious X Server, a remote attacker could possibly use this issue to cause libx11 to crash, resulting in a denial of service. Update Instructions: Run `sudo pro fix USN-6168-2` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: libx11-6 – 2:1.6.3-1ubuntu2.2+esm2 libx11-data – 2:1.6.3-1ubuntu2.2+esm2 libx11-xcb-dev – 2:1.6.3-1ubuntu2.2+esm2 libx11-xcb1 – 2:1.6.3-1ubuntu2.2+esm2 libx11-doc – 2:1.6.3-1ubuntu2.2+esm2 libx11-dev – 2:1.6.3-1ubuntu2.2+esm2 Available with Ubuntu Pro (Infra-only):

CVEs contained in this USN include: CVE-2023-3138.

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • 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:

  • CF Deployment
    • Upgrade all versions to 30.0.0 or greater


2023-08-04: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR