Comment by emerose

I don't have any inside information on this, but my guess is that this is going to come down to confusion about 302/303/307 redirects. In theory, clients receiving a 302 in response to a POST are supposed to re-send the POST wherever the redirect leads; in practice, clients do all kinds of different things. This feels like just the kind of weird edge case that defeats fragile security mechanisms like crossdomain.xml.