This issue plagued me for way longer than it should. Due to lack of documentation online I figured it would be best to represent it here.
I kept getting Black-holed. The most common answer I found online was to disable security altogether. (Seriously, don't do that). Rather, the correct answer via consensus in the #CakePHP IRC, as well as multiple other hidden forum posts was to disable it on a per hidden field basis.
Easy answer. Make this:Into this: (The last one didn't work for me as was vastly suggested, but the following worked for me and should be an alternate) Happy coding!