CVE-2021-3602

Buildah processes using chroot isolation may leak environment values to intermediate processes

Workarounds

As a workaround, invoking buildah in a container under env -i to have it started with a reinitialized environment should prevent the leakage.

For more information

If you have any questions or comments about this advisory:

• Open an issue in buildah
• Email us at the buildah general mailing list, or the podman security mailing list if it's sensitive.

When running processes using "chroot" isolation, the process being run can examine the environment variables of its immediate parent and grandparent processes (CVE-2021-3602). This isolation type is often used when running buildah in unprivileged containers, and it is often used to do so in CI/CD environments. If sensitive information is exposed to the original buildah process through its environment, that information will unintentionally be shared with child processes which it starts as part of handling RUN instructions or during buildah run. The commands that buildah is instructed to run can read that information if they choose to.

CVE-2021-3602 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.16.8, 1.17.2, 1.19.9, 1.21.3); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Users should upgrade packages, or images which contain packages, to include version 1.21.3 or later.

1. What is CVE-2021-3602? CVE-2021-3602 is a medium-severity security vulnerability in github.com/containers/buildah (go), affecting versions <= 1.16.7. It is fixed in 1.16.8, 1.17.2, 1.19.9, 1.21.3.
2. How severe is CVE-2021-3602? CVE-2021-3602 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/containers/buildah are affected by CVE-2021-3602? github.com/containers/buildah (go) versions <= 1.16.7 is affected.
4. Is there a fix for CVE-2021-3602? Yes. CVE-2021-3602 is fixed in 1.16.8, 1.17.2, 1.19.9, 1.21.3. Upgrade to this version or later.
5. Is CVE-2021-3602 exploitable, and should I be worried? Whether CVE-2021-3602 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-3602 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-3602?
   • Upgrade github.com/containers/buildah to 1.16.8 or later
   • Upgrade github.com/containers/buildah to 1.17.2 or later
   • Upgrade github.com/containers/buildah to 1.19.9 or later
   • Upgrade github.com/containers/buildah to 1.21.3 or later

Other vulnerabilities in github.com/containers/buildah