is it legal to rescind offers if deposit was already processed?

i’ve been seeing a lot of offers being rescinded, some at my prospective school (Cornell). as far as i know, those offers were still in the air.

although it isn’t illegal to rescind unaccepted offers (as i understand it) do i have anything to worry about if i already accepted?

is that 500 deposit really legally binding? i’m not sure of the laws on this topic.

it might be a stupid question but i’m genuinely concerned that my offer is still able to be pulled from under my feet.