Why do the signatories want the Fable 5 export controls lifted?

The signatories argue that the export controls on Fable 5 and Mythos 5 hurt defenders more than attackers. They say cutting US security teams off from frontier models is a strategic loss while attackers can still reach equivalent systems, naming GPT-5.5, Claude Opus 4.8, and Chinese frontier models as comparable. The letter calls the directive misguided.

What triggered the ban on Fable 5 and Mythos 5?

A third-party paper triggered the export-control directive. Katie Moussouris, the only outside expert to read it, says the so-called jailbreak was researchers asking the model to 'fix this code' after a request to 'review for vulnerabilities' was refused. The letter argues that patching a vulnerable file inherently requires identifying the vulnerability, which is standard defender work.

What does the FreeFable letter ask the government to do?

The FreeFable letter asks the White House to lift the export-control directive on Anthropic's Fable 5 and Mythos 5 models. It also asks for future AI regulation to be scientific, transparent, and restrictive only to the minimal extent necessary. The letter is addressed to Secretary Lutnick and National Cyber Director Cairncross.

FreeFable Coalition · 2026-06-14 · major

FreeFable — 300+ security leaders ask the White House to lift the Fable 5 ban

Bruce Schneier, Alex Stamos, Katie Moussouris and 300+ cybersecurity executives sign an open letter calling the export controls on Anthropic's Fable 5 and Mythos 5 a 'misguided' action that hurts defenders more than attackers.

FreeFable open letter banner asking the White House to lift Fable 5 and Mythos 5 export controls

Bruce Schneier, Alex Stamos, Katie Moussouris and 300+ security execs publicly ask the White House to reverse the Fable 5 and Mythos 5 export controls.

Key specs

Signatories	300+
Models affected	Fable 5, Mythos 5

Quick facts

Type	Open letter
From	FreeFable Coalition (300+ cybersecurity leaders)
Addressed to	U.S. White House (Sec. Lutnick, National Cyber Director Cairncross)
Models affected	Anthropic Fable 5 and Mythos 5
The ask	Lift the export-control directive that took the models offline on June 12, 2026
Notable signatories	Bruce Schneier, Alex Stamos, Katie Moussouris, Casey Ellis, Rachel Tobac, Paul Vixie

What is it?

FreeFable is an open letter signed by over 300 cybersecurity executives, researchers, and CISOs urging the White House to lift the export-control directive that took Anthropic's Fable 5 and Mythos 5 offline on June 12. Signatories include Bruce Schneier, Alex Stamos, Katie Moussouris of Luta Security, Bugcrowd's Casey Ellis, Rachel Tobac of SocialProof Security, and Paul Vixie.

How does it work?

Moussouris — the only outside expert to read the third-party paper that triggered the ban — says the so-called jailbreak was researchers asking the model to 'fix this code' after a 'review for vulnerabilities' request was refused. Patching a vulnerable file inherently requires identifying the vulnerability. The letter argues this is standard defender work and that comparable capabilities exist in GPT-5.5, Claude Opus 4.8, and Chinese frontier models. The signatories ask for scientific, transparent, and minimally restrictive future regulation.

Why does it matter?

Anthropic's Fable 5 and Mythos 5 have been offline since June 12. The signatories say cutting defenders off from frontier models while attackers can still reach equivalent systems is a strategic loss. The letter and parallel reporting from The Atlantic, TechCrunch, Axios, and Fortune are now the public counter-pressure on the directive — a major test of how AI export controls will be applied going forward.

Who is it for?

security researchers, AI policy watchers, anyone tracking the Fable 5 fallout

Frequently asked questions

What is the FreeFable open letter?: FreeFable is an open letter signed by over 300 cybersecurity executives, researchers, and CISOs. The letter urges the White House to lift the export-control directive that took Anthropic's Fable 5 and Mythos 5 models offline on June 12, 2026. Signatories include Bruce Schneier, Alex Stamos, Katie Moussouris, Casey Ellis, Rachel Tobac, and Paul Vixie.
Why do the signatories want the Fable 5 export controls lifted?: The signatories argue that the export controls on Fable 5 and Mythos 5 hurt defenders more than attackers. They say cutting US security teams off from frontier models is a strategic loss while attackers can still reach equivalent systems, naming GPT-5.5, Claude Opus 4.8, and Chinese frontier models as comparable. The letter calls the directive misguided.
What triggered the ban on Fable 5 and Mythos 5?: A third-party paper triggered the export-control directive. Katie Moussouris, the only outside expert to read it, says the so-called jailbreak was researchers asking the model to 'fix this code' after a request to 'review for vulnerabilities' was refused. The letter argues that patching a vulnerable file inherently requires identifying the vulnerability, which is standard defender work.
What does the FreeFable letter ask the government to do?: The FreeFable letter asks the White House to lift the export-control directive on Anthropic's Fable 5 and Mythos 5 models. It also asks for future AI regulation to be scientific, transparent, and restrictive only to the minimal extent necessary. The letter is addressed to Secretary Lutnick and National Cyber Director Cairncross.

Try it

https://freefable.org