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Security Advisory

USN-6409-1: GNU C Library vulnerabilities

USN-6409-1: GNU C Library vulnerabilities




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 22.04


It was discovered that the GNU C Library incorrectly handled the GLIBC_TUNABLES environment variable. An attacker could possibly use this issue to perform a privilege escalation attack. (CVE-2023-4911) It was discovered that the GNU C Library incorrectly handled certain DNS responses when the system was configured in no-aaaa mode. A remote attacker could possibly use this issue to cause the GNU C Library to crash, resulting in a denial of service. This issue only affected Ubuntu 23.04. (CVE-2023-4527) Update Instructions: Run `sudo pro fix USN-6409-1` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: libc-bin – 2.35-0ubuntu3.4 glibc-doc – 2.35-0ubuntu3.4 locales-all – 2.35-0ubuntu3.4 libc6-i386 – 2.35-0ubuntu3.4 libc6-s390 – 2.35-0ubuntu3.4 libc6-dev-i386 – 2.35-0ubuntu3.4 nscd – 2.35-0ubuntu3.4 libc6-dev-x32 – 2.35-0ubuntu3.4 libc6-dev – 2.35-0ubuntu3.4 libc6-amd64 – 2.35-0ubuntu3.4 libc6-x32 – 2.35-0ubuntu3.4 libc6-dev-amd64 – 2.35-0ubuntu3.4 libc-dev-bin – 2.35-0ubuntu3.4 libc6 – 2.35-0ubuntu3.4 libc6-prof – 2.35-0ubuntu3.4 libc-devtools – 2.35-0ubuntu3.4 glibc-source – 2.35-0ubuntu3.4 libc6-dev-s390 – 2.35-0ubuntu3.4 locales – 2.35-0ubuntu3.4 No subscription required

Affected Cloud Foundry Products and Versions

Severity is unknown unless otherwise noted.

  • cflinuxfs4
    • All versions prior to 1.40.0
  • Jammy Stemcells
    • 1.x versions prior to 1.250
    • All other stemcells not listed.
  • CF Deployment
    • All versions with Jammy Stemcells prior to 1.250


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 1.40.0 or greater
  • Jammy Stemcells
    • Upgrade 1.x versions to 1.250 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • For all versions, upgrade Jammy Stemcells to 1.250 or greater



2024-03-18: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR