The OAuth 2.0 specification's authorization code mechanism includes redirect URI checking from the site you redirect to. See steps D and E in section 4.1 of the spec. Also, section 4.1.3 describes in ...
The W3C CORS recommendation states: Certain types of resources should not attempt to specify particular authorized origins, but instead either deny or allow all origins. ... 3. A GET ...
http://tools.ietf.org/html/draft-ietf-oauth-v2-30#section-10.12 says: The client MUST implement CSRF protection [...] typically accomplished by requiring any request sent to the redirection URI ...