Environment Variable Injection in GitHub Actions

Impact

The @actions/core npm module addPath and exportVariable functions communicate with the Actions Runner over stdout by generating a string in a specific format. Workflows that log untrusted data to stdout may invoke these commands, resulting in the path or environment variables being modified without the intention of the workflow or action author.

Patches

The runner will release an update that disables the set-env and add-path workflow commands in the near future. For now, users should upgrade to @actions/core v1.2.6 or later, and replace any instance of the set-env or add-path commands in their workflows with the new Environment File Syntax. Workflows and actions using the old commands or older versions of the toolkit will start to warn, then error out during workflow execution.

Workarounds

None, it is strongly suggested that you upgrade as soon as possible.

For more information

If you have any questions or comments about this advisory:

• Open an issue in Actions Toolkit