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Security Advisory

USN-6237-2: curl regression




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 22.04


USN-6237-1 fixed vulnerabilities in curl. The update caused a certificate wildcard handling regression on Ubuntu 22.04 LTS. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Hiroki Kurosawa discovered that curl incorrectly handled validating certain certificate wildcards. A remote attacker could possibly use this issue to spoof certain website certificates using IDN hosts. (CVE-2023-28321) Hiroki Kurosawa discovered that curl incorrectly handled callbacks when certain options are set by applications. This could cause applications using curl to misbehave, resulting in information disclosure, or a denial of service. (CVE-2023-28322) It was discovered that curl incorrectly handled saving cookies to files. A local attacker could possibly use this issue to create or overwrite files. This issue only affected Ubuntu 22.10, and Ubuntu 23.04. (CVE-2023-32001) Update Instructions: Run `sudo pro fix USN-6237-2` to fix the vulnerability. The problem can be corrected by updating your system to the following package versions: libcurl4-gnutls-dev – 7.81.0-1ubuntu1.13 libcurl4-openssl-dev – 7.81.0-1ubuntu1.13 libcurl3-gnutls – 7.81.0-1ubuntu1.13 libcurl4-doc – 7.81.0-1ubuntu1.13 libcurl3-nss – 7.81.0-1ubuntu1.13 libcurl4-nss-dev – 7.81.0-1ubuntu1.13 libcurl4 – 7.81.0-1ubuntu1.13 curl – 7.81.0-1ubuntu1.13 No subscription required

Affected Cloud Foundry Products and Versions

Severity is unknown unless otherwise noted.

  • cflinuxfs4
    • All versions prior to 1.23.0
  • Jammy Stemcells
    • 1.x versions prior to 1.179
    • All other stemcells not listed.
  • CF Deployment
    • All versions with Jammy Stemcells prior to 1.179


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 1.23.0 or greater
  • Jammy Stemcells
    • Upgrade 1.x versions to 1.179 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • For all versions, upgrade Jammy Stemcells to 1.179 or greater



2023-08-10: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR