Blocking of Anthropic’s AI models: China is said to have had access to Mythos

The US government has ordered the shutdown of Anthropic’s Fable 5 and Mythos 5 AI models, among other things, because of suspicions that a group with ties to the Chinese government had access to the latter. This is reported by the US magazine Semafor, citing an anonymous source. This could explain why not only the limited Fable 5 but also Mythos 5 had to be banned. Access to the latter was actually strictly regulated. If the People’s Republic has access to it, it could pose a risk to US national security, writes Semafor. However, confirmation is pending. So far it has been said that there was a way to bypass Fable 5’s protection mechanisms, which is why the ban was ordered.

Bumpy start and U-turn

Anthropic released Fable 5 last Tuesday as a content-restricted variant of the new Mythos 5. Initial tests had confirmed the noticeably higher performance of the AI ​​model, but also led to criticism of the security measures. If a so-called classifier classified a query as sensitive, it was not Fable that answered the question, but the older model Claude Opus 4.8. Anthropic wanted to prevent attackers from exploiting the model’s capabilities for cyberattacks or other malicious purposes. But this could also happen with “safe, normal content,” according to a note. The approach caused a lot of criticism.

On Friday, Anthropic unexpectedly blocked access to Fable 5 and Mythos 5 – for all users worldwide. The trigger was allegedly an export control directive from the US government that prohibits foreign nationals from accessing both models – including foreign Anthropic employees within the US. At the weekend it was said that Amazon CEO Andy Jassy had previously reported to US Treasury Secretary Scott Bessent about a suspected jailbreak. The basis is said to have been a report from his company’s cybersecurity department, in which the alleged jailbreak was explained. It only became known later that the People’s Republic of China was said to have had access to Mythos. The exact background therefore remains unclear.

(my)