Composer is a dependency manager for PHP. On the 2.x branch prior to versions 2.2.24 and 2.7.7, the `composer install` command running inside a git/hg repository which has specially crafted branch names can lead to command injection. This requires cloning untrusted repositories. Patches are available in version 2.2.24 for 2.2 LTS or 2.7.7 for mainline. As a workaround, avoid cloning potentially compromised repositories.
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.