Skip to main content

Use `shell=False` in `subprocess` Function Calls


ImportanceReview GuidanceRequires Scanning Tool
HighMerge After Cursory ReviewNo

This codemod sets the shell keyword argument to False in subprocess module function calls that have set it to True.

Setting shell=True will execute the provided command through the system shell which can lead to shell injection vulnerabilities. In the worst case this can give an attacker the ability to run arbitrary commands on your system. In most cases using shell=False is sufficient and leads to much safer code.

The changes from this codemod look like this:

 import subprocess
-"echo 'hi'", shell=True)
+"echo 'hi'", shell=False)

If you have feedback on this codemod, please let us know!


Why is this codemod marked as Merge After Cursory Review?

In most cases setting shell=False is correct and leads to much safer code. However there are valid use cases for shell=True when using shell functionality like pipes or wildcard is required. In such cases it is important to run only trusted, validated commands.

Codemod Settings