it's offered in polymarket.
https://www.ainvest.com/news/betting-odds-strike-iran-surge-32-67-polymarket-2506/But my personal take. I think this kind of possibility shouldn’t be something people can bet on. It should be illegal to offer wagers like this. I don’t see it in regulated sportsbooks, so I guess they’re complying with the rules.
But since Polymarket isn’t regulated, they can offer it. Still, I think it’s unethical. We shouldn’t be hoping for a war to happen, so betting on it just shouldn’t exist.
Polymarket is notorious for hosting some weird events of which the war was one of their favorite which they will never miss for anything in the world. On the ethics of such practice, I don't think I know what should be done about it but the truth remain that do it purely as business and not that they approve of it. I think that if their action is seen as a threat in any form, they would have been shutdown a long time ago. You should just see it from the business perspective and not on the basis of ethics.