I'd personally use the sudo approach that ivanatora recommended, but there are other ways of achieving the same result.

• Have a daemon running with the correct permissions, that the CGI script can connect to, and signal to run the necessary commands.
• If immediate timing isn't necessary, write a message to a directory, and have a cronjob check for messages and finish processing them as root.
• You can also kick off a single script w/ sudo, which then runs all of the other commands.

Each one of these suggestions has additional problems -- the first one, some other process might connect; the second has a directory writable by 'nobody', which means all scripts on the webserver; the third one will need the script protected so no one modifies it.

You can mitigate some of the concerns by using suEXEC or CGIwrap on the webserver. (both of which allow cgis to be run as someone other than the webserver's default user)