Vulnerability Description
Composer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::generateP4Command() method, which constructs shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker can inject arbitrary commands through these values in a malicious composer.json declaring a Perforce VCS repository, leading to command execution in the context of the user running Composer, even if Perforce is not installed. VCS repositories are only loaded from the root composer.json or the composer config directory, so this cannot be exploited through composer.json files of packages installed as dependencies. Users are at risk if they run Composer commands on untrusted projects with attacker-supplied composer.json files. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline).
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Getcomposer | Composer | >= 1.0.0, <= 2.2.26 |
Related Weaknesses (CWE)
References
- https://github.com/composer/composer/releases/tag/2.9.6Release Notes
- https://github.com/composer/composer/security/advisories/GHSA-wg36-wvj6-r67pVendor Advisory
FAQ
What is CVE-2026-40176?
CVE-2026-40176 is a vulnerability with a CVSS score of 7.8 (HIGH). Composer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::generateP4Command() method, which constructs shel...
How severe is CVE-2026-40176?
CVE-2026-40176 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40176?
Check the references section above for vendor advisories and patch information. Affected products include: Getcomposer Composer.