In Asterisk 11.x before 11.25.2, 13.x before 13.17.1, and 14.x before14.6.1 and Certified Asterisk 11.x before 11.6-cert17 and 13.x before13.13-cert5, unauthorized command execution is possible. The app_minivmmodule has an "externnotify" program configuration option that is executed by the MinivmNotify dialplan application. The application uses the caller-id name and number as part of a built string passed to the OS shell for interpretation and execution. Since the caller-id name and number can come from an untrusted source, a crafted caller-id name or number allows an arbitrary shell command injection.