Package Instance

Buildah processes using chroot isolation may leak environment values to intermediate processes
### 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](https://github.com/containers/buildah/issues)
* Email us at [the buildah general mailing list](mailto:buildah@lists.buildah.io), or [the podman security mailing list](mailto:security@lists.podman.io) if it's sensitive.