This is really a vulnerability that applies in any case where you pass user supplied arguments to a command line program. Suppose you have a bunch of files on a

This is really a vulnerability that applies in any case where you pass user supplied arguments to a command line program. Suppose you have a bunch of files on a server and you allow the user to send a list of files that they want to download as tar. You're careful to avoid directory traversal attacks so you reject filenames that contain slashes. Then, you do: exec(["tar", "cz", ...user_wanted_files]) The user sends you a GET /api/storage/download_tar?files=--checkpoint%3D1&files=--checkpoint-action%3Dexec%3Dsh+shell.sh which causes you to execute the contents of shell.sh. No shell, no glob necessary. To do it correctly, you would have to do: exec(["tar", "cz", "--", ...user_wanted_files]) Or add ./ to the start of each filename.