(Not the parent but) one cool CGI-specific problem that always comes to mind is HTTPoxy: https://www.ionos.co.uk/digitalguide/server/configuration/httpoxy-behi

(Not the parent but) one cool CGI-specific problem that always comes to mind is HTTPoxy: https://www.ionos.co.uk/digitalguide/server/configuration/httpoxy-behind-the-cgi-vulnerability/ https://www.ionos.co.uk/digitalguide/server/configuration/ht... You could write this off as a library implementation problem, but it comes about because of unfortunate mapping of HTTP parameters to well-known environment variables in CGI, and has tripped up multiple library authors.