Composer Remote Code Execution vulnerability via web-accessible composer.pharGHSA-jm6m-4632-36hf
HIGHFix: composer/composer@4fce147GHSA-jm6m-4632-36hf is a high-severity (CVSS 8.8) CWE-74 vulnerability in composer/composer. A fix is available for composer/composer — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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-jm6m-4632-36hf.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
composer/composer🐘composer/composer🐘composer/composerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Composer is a dependency manager for PHP. Users publishing a composer.phar to a public web-accessible server where the composer.phar can be executed as a php file may be subject to a remote code execution vulnerability if PHP also has register_argc_argv enabled in php.ini. Versions 2.6.4, 2.2.22 and 1.10.27 patch this vulnerability. Users are advised to upgrade. Users unable to upgrade should make sure register_argc_argv is disabled in php.ini, and avoid publishing composer.phar to the web as this is not best practice.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | composer/composer | all versions | 1.10.27composer require composer/composer:^1.10.27 |
| 🐘Packagist | composer/composer | ≥ 2.0.0&&< 2.2.22 | 2.2.22composer require composer/composer:^2.2.22 |
| 🐘Packagist | composer/composer | ≥ 2.3.0&&< 2.6.4 | 2.6.4composer require composer/composer:^2.6.4 |
Affected Products
debian linuxdebianfedorafedoraprojectcomposergetcomposerDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for composer/composer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update composer/composer to 1.10.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jm6m-4632-36hf 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.
Frequently Asked Questions
Is GHSA-jm6m-4632-36hf in your dependencies?
Find it across Packagist, including transitive dependencies.