title: GitHub Action tj-actions/verify-changed-files is vulnerable to command injection in output filenames
description: The [`tj-actions/verify-changed-files`](https://github.com/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`](https://github.com/tj-actions/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](https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners) 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](https://github.com/tj-actions/verify-changed-files/releases/tag/v17) and [17.0.0](https://github.com/tj-actions/verify-changed-files/releases/tag/v17.0.0) by enabling `safe_output` by default and returning filename paths escaping special characters for bash environments.
problem types: CWE-20: Improper Input Validation
affected:
{
vendor: tj-actions
product: verify-changed-files
versions:
version: < 17.0.0, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 7.7
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: LOW
privilegesRequired: LOW
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
version: 3.1
]