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).
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.
Composer is a dependency manager for PHP. In versions on the 2.x branch prior to 2.2.26 and 2.9.3, attackers controlling remote sources that Composer downloads from might in some way inject ANSI control characters in the terminal output of various Composer commands, causing mangled output and potentially leading to confusion or DoS of the terminal application. There is no proven exploit and this has thus a low severity but we still publish a CVE as it has potential for abuse, and we want to be on the safe side informing users that they should upgrade. Versions 2.2.26 and 2.9.3 contain a patch for the issue.
Composer is a dependency Manager for the PHP language. In affected versions several files within the local working directory are included during the invocation of Composer and in the context of the executing user. As such, under certain conditions arbitrary code execution may lead to local privilege escalation, provide lateral user movement or malicious code execution when Composer is invoked within a directory with tampered files. All Composer CLI commands are affected, including composer.phar's self-update. The following scenarios are of high risk: Composer being run with sudo, Pipelines which may execute Composer on untrusted projects, Shared environments with developers who run Composer individually on the same project. This vulnerability has been addressed in versions 2.7.0 and 2.2.23. It is advised that the patched versions are applied at the earliest convenience. Where not possible, the following should be addressed: Remove all sudo composer privileges for all users to mitigate root privilege escalation, and avoid running Composer within an untrusted directory, or if needed, verify that the contents of `vendor/composer/InstalledVersions.php` and `vendor/composer/installed.php` do not include untrusted code. A reset can also be done on these files by the following:```sh
rm vendor/composer/installed.php vendor/composer/InstalledVersions.php
composer install --no-scripts --no-plugins
```