Command injection

The tj-actions/verify-changed-files action allows for command injection in changed filenames, allowing an attacker to execute arbitrary code and potentially leak secrets. The verify-changed-files workflow returns the list of files changed within a workflow execution. This could potentially allow filenames that contain special characters such as ; which can be used by an attacker to take over the GitHub Runner if the output value is used in a raw fashion (thus being directly replaced before execution) inside a run block. By running custom commands, an attacker may be able to steal secrets such as GITHUB_TOKEN if triggered on other events than pull_request.

This has been patched in versions 17 and 17.0.0 by enabling safe_output by default and returning filename paths escaping special characters for bash environments.