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MEDIUM severity

GHSA-5wxr-w449-57cm

MEDIUMFix: shivammathur/setup-php@7748c24

GHSA-5wxr-w449-57cm is a medium-severity (CVSS 5.9) vulnerability in shivammathur/setup-php. O3 Security confirms whether GHSA-5wxr-w449-57cm is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Setup PHP: GitHub tokens configured by setup-php may be exposed through pinned affected Composer versions

Published
May 20, 2026
Updated
May 20, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of May 20, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
📦shivammathur/setup-php

Real-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

Impact

This affects only workflows that pin an exact affected Composer semver version through setup-php, for example tools: composer:2.9.7.

Workflows using the default Composer version, composer:v2, or no pinned Composer version are not affected through setup-php, because those Composer URLs have been updated to patched Composer releases for all setup-php versions.

setup-php does not directly print the token. The token may be exposed through Composer when Composer validates github-oauth auth and rejects GitHub's newer hyphen-containing token format.

Public repository logs may expose the token. GitHub-hosted runner GITHUB_TOKEN values expire after the job, but exposure may still matter during the token lifetime and for longer-lived GitHub App or user tokens.

Patches

setup-php 2.37.1 skips generated GitHub OAuth auth for pinned Composer versions affected by Composer GHSA-f9f8-rm49-7jv2 while preserving other Composer auth, including Packagist auth.

Workarounds

Upgrade to setup-php 2.37.1 or newer. You can also avoid the affected path by using a patched Composer version: 2.9.8, 2.2.28, 1.10.28, or newer supported Composer releases.

It is recommended to avoid pinning affected Composer versions such as composer:2.9.7, unless you have automations to do timely updates in your workflows.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦GitHub Actionsshivammathur/setup-phpall versions2.37.1

Detection & mitigation playbook

Open-source dependency
  1. Detect

    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.

  2. 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-5wxr-w449-57cm is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-5wxr-w449-57cm 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-5wxr-w449-57cm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact This affects only workflows that pin an exact affected Composer semver version through setup-php, for example `tools: composer:2.9.7`. Workflows using the default Composer version, `composer:v2`, or no pinned Composer version are not affected through setup-php, because those Composer URLs have been updated to patched Composer releases for all setup-php versions. setup-php does not directly print the token. The token may be exposed through Composer when Composer validates github-oauth auth and rejects GitHub's newer hyphen-containing token format. Public repository logs may expose
O3 Security · Impact-Aware SCA

Is GHSA-5wxr-w449-57cm in your dependencies?

O3 detects GHSA-5wxr-w449-57cm 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.

GHSA-5wxr-w449-57cm: shivammathur/setup… | O3 Security