How far will the Iran war spillover?

It's been a week since the war between Israel, the United States and Iran started with strikes on Tehran. The conflict soon spread to neighbouring countries, who've been on the receiving end of hundreds of Iranian missiles and drones. Targets in countries beyond the region have also been hit, with some warning those attacks could open new fronts. Iran's President Masoud Pezeshkian has now apologised to Gulf states - saying it will limit its attacks on them in future. But with no sign that Israel and the US will end the war, how likely are its effects to spread?