GHSA-pqwm-q9pv-ph8r is a medium-severity (CVSS 5.6) OS Command Injection vulnerability in shivammathur/setup-php. O3 Security confirms whether GHSA-pqwm-q9pv-ph8r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Setup PHP: Command Injection in Repository-Derived PHP Version Resolution
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-pqwm-q9pv-ph8r.
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-pqwm-q9pv-ph8r 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 360,482 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
shivammathur/setup-phpReal-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
A command injection vulnerability was identified in shivammathur/setup-php when the action resolves the PHP version from repository-controlled files and uses that value while generating the platform setup script.
In affected versions, setup-php may read the PHP version from:
.php-versioncomposer.lockviaplatform-overrides.phpcomposer.jsonviaconfig.platform.php
If an attacker can influence one of these files and the workflow executes setup-php in a trusted context, they may be able to execute commands on the GitHub Actions runner.
Impact
This issue is exploitable when setup-php is run after checking out attacker-controlled repository contents and resolves the PHP version from repository files.
The most significant example is a privileged workflow such as pull_request_target that checks out untrusted pull request code before invoking setup-php. Similar risk can also arise in other workflows that operate on attacker-controlled refs, branches, or repository contents in a trusted context.
This is not a separate security boundary when an attacker can already modify the workflow definition itself or directly control the php-version workflow input, since that level of access already permits arbitrary command execution in GitHub Actions.
Technical details
In affected versions, repository-derived PHP version values were insufficiently constrained before being incorporated into the generated shell or PowerShell setup script executed by the action. This could allow attacker-controlled values from supported repository files to influence script execution in trusted workflow contexts.
Remediation
If you are using shivammathur/setup-php@v2, no action is needed on your end. Users who pin the setup-php release version or release version SHA should upgrade to a patched version.
The fix validates PHP version inputs, constrains manifest-derived versions, hardens script generation at the execution, and includes additional checks in related input-handling paths.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | shivammathur/setup-php | ≥ 2.25.0&&< 2.37.1 | 2.37.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for shivammathur/setup-php. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update shivammathur/setup-php to 2.37.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pqwm-q9pv-ph8r 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 pinpoints whether GHSA-pqwm-q9pv-ph8r is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-pqwm-q9pv-ph8r. 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-pqwm-q9pv-ph8r in your dependencies?
O3 detects GHSA-pqwm-q9pv-ph8r across GitHub Actions dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.