Yes, that can happen. UEFA preselects the host stadiums before the tournament even starts. If Osasuna had their stadium picked over 12 months before and they managed to make the final, good on them.
Real Madrid (1957, won), Inter Milan (1965, won) and AS Roma (1984, lost) have all played at their home ground during a European Cup/Champions League final. Up until the 1996-97 season the UEFA Cup was played over two legs, with each team playing a leg at home. Since then Feyenoord hosted and won the 2002 UEFA Cup.
No glitches.