GHSA-ghm2-rq8q-wrhc is a high-severity (CVSS 7.7) Improper Input Validation vulnerability in tj-actions/verify-changed-files. 1 public exploit reference exists, so weaponization risk is real. A fix is available for tj-actions/verify-changed-files — see the affected versions and patch details below.
Potential Actions command injection in output filenames (GHSL-2023-275)
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-ghm2-rq8q-wrhc plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
tj-actions/verify-changed-filesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
Details
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 ; and ` (backtick) 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. For example on push.
Proof of Concept
- Submit a pull request to the repository with a new file injecting a command. For example
$(whoami).txtwould be a valid filename. - Upon approval of the workflow (triggered by the pull request), the action will get executed and the malicious pull request filename will flow into the
List all changed files tracked and untracked filesstep.
- name: List all changed files tracked and untracked files
run: |
echo "Changed files: ${{ steps.verify-changed-files.outputs.changed_files }}"
Example output:
##[group]Run echo "Changed files: $(whoami).txt"
echo "Changed files: $(whoami).txt"[0m
shell: /usr/bin/bash -e {0}
##[endgroup]
Changed files: runner.txt
Impact
This issue may lead to arbitrary command execution in the GitHub Runner.
Resolution
-
A new
safe_outputinput would be enabled by default and return filename paths escaping special characters like ;, ` (backtick), $, (), etc for bash environments. -
A safe recommendation of using environment variables to store unsafe outputs.
- name: List all changed files tracked and untracked files
env:
CHANGED_FILES: ${{ steps.verify-changed-files.outputs.changed_files }}
run: |
echo "Changed files: $CHANGED_FILES"
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | tj-actions/verify-changed-files | all versions | 17 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tj-actions/verify-changed-files, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tj-actions/verify-changed-files to 17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-ghm2-rq8q-wrhc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-ghm2-rq8q-wrhc can be triaged on real exposure rather than presence alone.
Tailored to GHSA-ghm2-rq8q-wrhc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-ghm2-rq8q-wrhc in your dependencies?
O3 Security finds GHSA-ghm2-rq8q-wrhc across GitHub Actions dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.