The (1) make_nonce, (2) generate_nonce, and (3) generate_verifier functions in SimpleGeo python-oauth2 uses weak random numbers to generate nonces, which makes it easier for remote attackers to guess the nonce via a brute force attack.
https://github.com/simplegeo/python-oauth2/pull/146
https://github.com/simplegeo/python-oauth2/issues/9