What can I do if I want to take an upper-year CISC course and don't satisfy this requirement?
If possible, transfer to a degree program that has the desired course as a requirement or option; how to do this is explained here. If this is not feasible (for example, because you want to finish another degree first), ask an academic adviser to give you permission to take the course.
I'm taking a program that requires an upper-year CISC course (or that allows such a course as an option) but is not a Computing program. Do I need to get permission to take the course?
No. You do not need special permission.