Cloud Foundry Logo
blog single gear
Security Advisory

USN-6539-1: python-cryptography vulnerabilities

USN-6539-1: python-cryptography vulnerabilities




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 22.04


It was discovered that the python-cryptography Cipher.update_into function would incorrectly accept objects with immutable buffers. This would result in corrupted output, contrary to expectations. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, and Ubuntu 23.04. (CVE-2023-23931) It was dicovered that python-cryptography incorrectly handled loading certain PKCS7 certificates. A remote attacker could possibly use this issue to cause python-cryptography to crash, resulting in a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 23.04, and Ubuntu 23.10. (CVE-2023-49083) Update Instructions: Run `sudo pro fix USN-6539-1` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: python3-cryptography – 3.4.8-1ubuntu2.1 python-cryptography-doc – 3.4.8-1ubuntu2.1 No subscription required

CVEs contained in this USN include: CVE-2023-23931, CVE-2023-49083.

Affected Cloud Foundry Products and Versions

Severity is medium unless otherwise noted.

  • Jammy Stemcells
    • 1.x versions prior to 1.327
    • All other stemcells not listed.
  • CF Deployment
    • All versions with Jammy Stemcells prior to 1.327


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

The Cloud Foundry project recommends upgrading the following releases:

  • Jammy Stemcells
    • Upgrade 1.x versions to 1.327 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • For all versions, upgrade Jammy Stemcells to 1.327 or greater


2024-04-04: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR