GHSA-PQWM-Q9PV-PH8R
Vulnerability from github – Published: 2026-05-20 15:31 – Updated: 2026-05-20 15:31Summary
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": [
{
"package": {
"ecosystem": "GitHub Actions",
"name": "shivammathur/setup-php"
},
"ranges": [
{
"events": [
{
"introduced": "2.25.0"
},
{
"fixed": "2.37.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-46420"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-20T15:31:52Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nA 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.\n\nIn affected versions, `setup-php` may read the PHP version from:\n\n- `.php-version`\n- `composer.lock` via `platform-overrides.php`\n- `composer.json` via `config.platform.php`\n\nIf 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.\n\n### Impact\n\nThis issue is exploitable when `setup-php` is run after checking out attacker-controlled repository contents and resolves the PHP version from repository files.\n\nThe 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.\n\nThis 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.\n\n### Technical details\n\nIn 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.\n\n### Remediation\n\nIf 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.\n\nThe fix validates PHP version inputs, constrains manifest-derived versions, hardens script generation at the execution, and includes additional checks in related input-handling paths.",
"id": "GHSA-pqwm-q9pv-ph8r",
"modified": "2026-05-20T15:31:52Z",
"published": "2026-05-20T15:31:52Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/shivammathur/setup-php/security/advisories/GHSA-pqwm-q9pv-ph8r"
},
{
"type": "WEB",
"url": "https://github.com/shivammathur/setup-php/commit/eeef37e059fb5368a5bc8ed8ce45ff54bd39b80b"
},
{
"type": "PACKAGE",
"url": "https://github.com/shivammathur/setup-php"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Setup PHP: Command Injection in Repository-Derived PHP Version Resolution"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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