The lighttpd does not set an empty QUERY_STRING variable for mod_cgi if no query string is used even though the RFC for CGI demands it. The URL has all details and also a working patch. Reproducible: Always
Thanks. We will track the upstream bug report.
It looks like 1.4.40 will fix this problem. I'm working on getting it into the tree, but fixing other bugs along the way. I'll mark this as IN_PROGRESS so others understand it's being worked on.
lighttpd 1.4.42 is now in testing. I'm adding the "InVCS" keyword to indicate this, and will close this bug once it stabilizes (in about a month, assuming no new bugs pop up).
lighttpd 1.4.42 is stable, closing.