The landing airbags would be in the wrong position to aid "right-side up" flotation on the CEV, nor are they neccessary, as the capsule will float quite well. The Apollo CM, in fact had two stable floating positions (pointy end up and pointy end down), and had small bags that deployed from the same area as where the parachutes were stored, in order to flip it back right-side up. I imagine the CEV will have the same floating characteristics. In the event of the crew needing to leave a floating capsule on their own (extremely unlikely), they would probably go out the top (docking hatch). Before using the side hatch on Apollo, the rescue swimmers attached a flotation collar that lifted the capsule higher, and also gave more protection against swamping from a wave getting in through the side hatch.