Impact The Perforce::syncCodeBase() method appended the $sourceReference parameter to a shell command without proper escaping, allowing an attacker to inject arbitrary commands through a crafted source reference containing shell metacharacters. Further as in GHSA-wg36-wvj6-r67p / CVE-2026-40176 the Perforce::generateP4Command() method constructed shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping from the source url field. Composer would execute these injected commands even if Perforce is not installed.

The source reference and url are provided as part of package metadata. Any Composer package repository can serve package metadata declaring perforce as a source type with a malicious source reference or source url. This means the vulnerability can be exploited through any package served by a compromised or malicious Composer repository. An attack does not require Perforce to be installed on the client, as Composer will attempt to execute the constructed command regardless.

This vulnerability is exploitable when installing or updating dependencies from source (--prefer-source, default when installing dev prefixed versions), even if you do not use Perforce.

Patches Fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline)

Note, the fix for the source url in the Perforce::generateP4Command() was addressed as part of the patches for GHSA-wg36-wvj6-r67p / CVE-2026-40176 in the same versions.

Workarounds

- Avoid installing dependencies from source by using --prefer-dist or the preferred-install: dist config setting. - Only use trusted Composer repositories.

Impact The Perforce::generateP4Command() method constructed shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker controlling a repository configuration in a malicious composer.json declaring a Perforce VCS repository could inject arbitrary commands through these values, leading to command execution in the context of the user running Composer. Composer would execute these injected commands even if Perforce is not installed.

VCS repositories are only loaded from the root composer.json file located in the directory you execute Composer commands in and from the composer config directory (e.g. ~/.config/composer/composer.json). So this vulnerability cannot be exploited through composer.json files of packages installed as dependencies.

You are at risk of command execution if you run Composer commands on untrusted projects with attacker supplied composer.json files, regardless of whether you or any of your dependencies use Perforce.

Patches Fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline)

Workarounds - Carefully inspect composer.json files before running Composer on them. Verify that Perforce-related fields contain valid values. - Only run Composer commands on projects from trusted sources.