Commerce export order pulls Anthropic's Fable 5 and Mythos 5 offline worldwide

A Friday letter from Howard Lutnick citing a narrow jailbreak forced a global shutdown. A growing cybersecurity coalition is asking for it to be reversed.

Anthropic pulled Fable 5 and Mythos 5 offline globally Friday night, hours after a directive letter from Commerce Secretary Howard Lutnick landed in Dario Amodei’s inbox at 5:21 p.m. ET placing both models under export controls covering all foreign nationals. The trigger, per Axios and Fortune, was a jailbreak demonstration assembled by an Amazon team and walked to the White House by Andy Jassy.

Anthropic’s own account of the technique is conspicuously dry. The exploit, the company says, “essentially consists of asking the model to read a specific codebase and fix any software flaws,” and the vulnerabilities it surfaces are “previously known, minor.” Anthropic calls it a “potential narrow, non-universal jailbreak” and notes it has so far received only verbal evidence. The same prompt class, the company adds, reproduces on other public models including OpenAI’s GPT-5.5; applying Lutnick’s standard industry-wide “would essentially halt all new model deployments for all frontier model providers.”

That last line is the strategic tell. A directive nominally about two Anthropic products implicates the entire frontier stack.

The pushback is now institutional. An open letter organized by Corridor CSO and former Facebook security chief Alex Stamos, addressed to Lutnick and National Cyber Director Sean Cairncross, argues the order “has taken the best models away from defenders, created market uncertainty, and risked America’s AI leadership without any real risk to justify it.” Cybersecurity Dive counted 76 signatures Monday morning; Fortune put the figure near 100, with names from Nvidia, Adobe, Google, Zoom, and Sophos. The letter warns that Chinese frontier models are “only months behind the best American models.”

The political subtext is harder to launder. Anthropic engaged Luta Security founder Katie Moussouris to review the Amazon report; Fortune reports the administration characterized her as a “radical Democrat.” An unnamed official told Axios the lockdown should lift “in the next few weeks,” once national-security systems are “hardened.” Pentagon CIO Kirsten Davies described the posture as “prioritizing national security.”

A jailbreak that asks a model to fix code has now produced a worldwide shutoff and a coalition letter. The export-control regime is being stress-tested in public, by its beneficiaries.