I have done ICN-BUD-ZRH on those two carriers very recently. I was on separate tickets so I booked a longer connection.
There is no transfer security in BUD. You have to clear Schengen immigration, go landside, upstairs, and then reclear security. 45min would be very tight for all of this. The immigration line for Schengen citizens moved reasonably quickly, the one for non-Schengen visitors not so much. Security was quick using fast track (C ticket or *G), regular line looked longer.

edited to add: My guess is that the OP is on an award ticket given the routing.