The package pdfkit from 0.0.0 are vulnerable to Command Injection where the URL is not properly sanitized.
https://security.snyk.io/vuln/SNYK-RUBY-PDFKIT-2869795
https://github.com/pdfkit/pdfkit/blob/master/lib/pdfkit/source.rb%23L44-L50
http://packetstormsecurity.com/files/171746/pdfkit-0.8.7.2-Command-Injection.html