> Edit: I might also be misinterpreting what I am seeing and it's actually weak logic that created the keys, in the sense that one could guess the private key?
As I understand it, the private key is supposed to be a number in the range [0, 2^256), but they actually generated a number in [0, 256) for these 8 intermediate certificates. Once you know there are so few possibilities, you can try them all ~instantly, so effectively everyone has the private keys. (And when I say "you can", I actually mean you, not some hypothetical more skilled version of you: even if you don't know anything about public key infrastructure, if you have access to an LLM, it can do it for you with a single prompt.)
As I understand it, the private key is supposed to be a number in the range [0, 2^256), but they actually generated a number in [0, 256) for these 8 intermediate certificates. Once you know there are so few possibilities, you can try them all ~instantly, so effectively everyone has the private keys. (And when I say "you can", I actually mean you, not some hypothetical more skilled version of you: even if you don't know anything about public key infrastructure, if you have access to an LLM, it can do it for you with a single prompt.)