GHSA-7638-r9r3-rmjj Buildah processes using chroot isolation may leak environment values to intermediate processes

• Go github.com/containers/buildah: < 1.16.8 → fixed in 1.16.8 • Go github.com/containers/buildah: >= 1.17.0, < 1.17.2 → fixed in 1.17.2 • Go github.com/containers/buildah: >= 1.18.0, < 1.19.9 → fixed in 1.19.9 • Go github.com/containers/buildah: >= 1.20.0, < 1.21.3 → fixed in 1.21.3

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