> In part, this is because Fable 5.1 can now be used to discover software vulnerabilities—though not to develop exploits for them

Generally once an exploit chain is described, developing the exploit is trivial.

If you're so inclined, discover the exploits using Fable 5.1 and then give that exploit to a model that doesn't have such compunctions (e.g. local LLM or an uncensored cloud model / model that's easier to jailbreak). I don't think Anthropic is really mitigating here anything in the real world other than PR narratives where media can report "Anthropic's model was used to develop the latest cyber attack".