Setup PHP: Command Injection in Repository-Derived PHP Version Resolution

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.6 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS

• CVE-2026-46420: 2.01% estimated exploitation activity in the next 30 days; percentile 80.88 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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-version - composer.lock via platform-overrides.php - composer.json via config.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 pullrequesttarget 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…

Published by the source

20 May 2026, 15:31 UTC

Last modified by the source

20 May 2026, 15:31 UTC

Source last checked

26 Oct 2026, 17:08 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pqwm-q9pv-ph8r

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# Patch Next advisory brief: CVE-2026-46420

Advisory: Setup PHP: Command Injection in Repository-Derived PHP Version Resolution
IDs: CVE-2026-46420, GHSA-pqwm-q9pv-ph8r
Record: https://patchnext.com/advisories/cve-2026-46420 (revision 1, source checked 26 Oct 2026, 17:08 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: shivammathur/setup-php 2.37.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- GitHub Actions shivammathur/setup-php: affected >= 2.25.0, < 2.37.1; fixed in 2.37.1

## Suggested inspection (read-only)
- GitHub Actions shivammathur/setup-php: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on shivammathur/setup-php.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-pqwm-q9pv-ph8r (GitHub-reviewed advisory GHSA-pqwm-q9pv-ph8r lists affected ranges: GitHub Actions shivammathur/setup-php >=2.25.0 <2.37.1)

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