White House Official David Sacks Says U.S. Imposed Export Controls on Anthropic’s Fable Over Security Bypass

A senior White House official said the U.S. government imposed export controls on Anthropic after a commercial version of its newly released Mythos-series model, Fable, was found to have a jailbreak method that could bypass safety guardrails.

According to ChainCatcher, White House AI and crypto affairs lead David Sacks wrote that while Fable includes safety protections, bypassing them could expose advanced cyberattack capabilities within Mythos.

Sacks said Anthropic had previously described Mythos as a “cyber weapon” requiring regulation, and argued that fixing such vulnerabilities should therefore be the company’s responsibility.

He said a partner trusted by both Anthropic and the U.S. government identified a way to circumvent Fable’s guardrails during testing. Sacks added that the U.S. government then asked Anthropic CEO Dario Amodei to fix the issue or take the model offline, but the request was refused.

Sacks said Anthropic characterized the vulnerability as “not serious,” a view he said conflicted with the assessment of the U.S. government and the testing partner.

He added that the government, in response, implemented export controls and wants Anthropic to address the security issue so the restrictions can be lifted and Fable can return to full release.

Sacks also denied that the move was related to a separate dispute involving the U.S. Department of Defense and Anthropic, saying the government recognizes Anthropic’s technical capabilities and believes the current issue could be resolved relatively easily.