Administrator command execution via chained unsafe exec calls

Command injection in LibreNMS 21.6.0 through 26.4.x allows remote authenticated users with administrator access to execute host commands. The Signal transport's deliverAlert function passes an insufficiently escaped signal-cli path and Recipient value to exec, and scripts/composer_wrapper.php forwards the injected argument into additional unsafe exec calls. An administrator must create and test a crafted Signal alert transport; successful exploitation runs arbitrary executables with the LibreNMS service's host privileges.