Composer has Command Injection via Malicious Perforce Reference

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::syncCodeBase() method, which appends the $sourceReference parameter to a shell command without proper escaping, and additionally in the Perforce::generateP4Command() method as in GHSA-wg36-wvj6-r67p / CVE-2026-40176, which interpolates user-supplied Perforce connection parameters (port, user, client) from the source url field without proper escaping. An attacker can inject arbitrary commands through crafted source reference or source url values containing shell metacharacters, even if Perforce is not installed. Unlike CVE-2026-40176, the source reference and url are provided as part of package metadata, meaning any compromised or malicious Composer repository can serve package metadata declaring perforce as a source type with malicious values. This vulnerability is exploitable when installing or updating dependencies from source, including the default behavior when installing dev-prefixed versions. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline). If developers are unable to immediately update, they can avoid installing dependencies from source by using --prefer-dist or the preferred-install: dist config setting, and only use trusted Composer repositories as a workaround.

Timeline

1. Apr 15, 2026, 8:56 PM UTCCVE published
2. Apr 16, 2026, 1:41 PM UTCCISA SSVC assessment

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

3. Jul 15, 2026, 1:01 AM UTCRecord last updated

Affected versions

• composer composer

  From 2.3.0 · fixed in 2.9.6; From 1.0.0 · 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 3