Anthropic Restores Claude Fable 5 After U.S. Lifts Jailbreak-Linked Export Controls

Summary: Anthropic restored Claude Fable 5 worldwide on July 1 after the U.S. Commerce Department lifted export controls imposed June 12, which had forced the company to shut both Fable 5 and Mythos 5 down for all users because it could not verify nationality in real time. The trigger was a jailbreak found by Amazon researchers that got the model to flag software flaws and, in one case, write code showing how a flaw could be abused; Anthropic trained a classifier it says blocks that technique in more than 99% of tries, routing blocked requests to the weaker Opus 4.8.
What's compelling: A single jailbreak prompt, found by a partner, was enough to take a frontier model offline for every user worldwide within days - and the government reached for export controls because Fable 5 never went through the voluntary pre-release review path set up by the June 2 executive order.

Read the original at The Hacker News ↗