According to the Diffie-Hellman key exchange get affected by logjam, and openID uses this to establish an association. So how this going to affect OpenID?
logjam is not (even remotely) a break of the Diffie-Hellman key exchange method. It is a weakness of the TLS protocol. It affects only sessions, not credentials. It will soon be fixed. I estimate zero impact on OpenID. The "bad guys" cannot do MITM, only governments and ISPs could (in principle) do MITM.