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CVE-2026-40176GHSA-WG36-WVJ6-R67PBIT-COMPOSER-2026-40176

Composer is vulnerable to Command Injection via Malicious Perforce Repository

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.9.6, 2.2.27
3 proofs of concept on GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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).

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • composer composer

    From 2.3 · fixed in 2.9.6; From 1.0 · fixed in 2.2.27

  • composer/composerPackagist

    From 2.3.0 · fixed in 2.9.6

  • composer/composerPackagist

    From 1.0.0 · fixed in 2.2.27

References 5

GitHub · composer/composer

GitHub · Saku0512/CVE-2026-40176-poc

GitHub · daptheHuman/cve-2026-40176-cve-2026-40261

GitHub · ikarolaborda/CVE-2026-40176