Comment by jcalvinowens

It's not wrong. The only thing preventing me from forging your certificate is my inability to generate a new cert which hashes to the same digest as what is in your cert's signature. I don't actually need the keys if I break the hash.

EDIT2: I'm doing a bad job of explaining this... you obviously need the keypair associated with the cert to initiate connections with it and not trigger MITM alerts. But if you break the hash function, you don't need the private key from the root cert, the verbatim signature from the original cert will appear to be valid when spliced into your forged cert if the hash digest computation on the forged cert is the same.