Stop leaking information across requests

[susnux]

%hash is false if the hash hasn't been assigned to, or if the hash is simply empty. This causes the environment from the second request (that is, the environment produced by the first request) to be saved as default if the first request had empty environment. This way, request after the first can get access to credentials set up by the first request.

Instead of fixing this, I'd much rather remove this old and buggy interface. However, 10 years of deprecation don't seem to have been enough for CGI::Fast to switch to the new and properly supported interface. :-(

This is CVE-2011-2766.

[susnux]

This one is from shadowcat