If you don't care about security ramifications you can just add

http        ALL=(ALL)       NOPASSWD: ALL
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assuming http is the user-account your cgi-script runs under and then run the command in your cgi-script as

system("sudo -u root <your_command>")
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It will then run as root and should not have permission problems.

That should get you started for a more secure setup later.

hth