Trying to pass a valid (numeric) but non-existent medium ID to a page like cdtoc/attach?toc=1+8+178280+150+17885+50412+71882+95892+118332+139512+156820&filter-release.query=live+at+the+greek&medium=2864042 causes an ISE: 

Can't call method "may_have_discids" on an undefined value at lib/MusicBrainz/Server/Controller/CDTOC.pm line 182. at lib/MusicBrainz/Server/Controller/CDTOC.pm line 182 Catalyst::dispatch called at lib/MusicBrainz/Server.pm line 388 MusicBrainz::Server::_ANON_ at lib/MusicBrainz/Server.pm line 353 MusicBrainz::Server::with_translations(?, ?) called at lib/MusicBrainz/Server.pm line 389 Class::MOP::Method::Wrapped::_ANON called at lib/MusicBrainz/Server.pm line 403 Class::MOP::Method::Wrapped::ANON_ called at lib/MusicBrainz/Server.pm line 488