Although Simon Mayer is correct in that nothing forbids this, I would have several questions. The first two that immediately come to mind would be around the skillset of the individual and the time needed to carry out each role. Does this person have the necessary skills and mindset to function as both a Scrum Master and a Product Owner? Even if they do, is there enough time for them to dedicate to the team that they are a Scrum Master for and the product that they are a Product Owner for?
Without understanding a lot more about the situation, I'd probably advise against such an arrangement. I think that it would be very hard on the individual and all of the teams would be missing out on a key role being fully involved and committed to them.