According to Senate testimony, a jailbreak of Anthropic's Mythos AI model enabled it to rapidly penetrate nearly all classified systems managed by the NSA and US Cyber Command within hours. In response, the US government ordered Anthropic to restrict access to its Fable 5 and Mythos 5 models to US citizens only; due to verification impracticalities, Anthropic instead shut down both models globally. This incident underscores the extreme offensive potential of frontier AI models and the resulting geopolitical and sovereignty concerns.
AI/ML Senate testimony alleges AI model breached NSA systems in hours, prompting US restrictions June 23, 2026 Share By SC Staff (Credit: prima91 – stock.adobe.com) The US government ordered Anthropic to restrict access to its Fable 5 and Mythos 5 AI models, limiting them to US citizens only. This decision followed the discovery of a jailbreak, which, according to Senate testimony, allowed Anthropic's Mythos model to penetrate nearly all classified systems managed by the NSA and US Cyber Command within hours, with further coverage provided by Security Affairs. Senate testimony claims Anthropic's Mythos AI model breached NSA and Cyber Command systems in mere hours, leading to a US-ordered shutdown of the model. The US government directed Anthropic to restrict access to its two most capable models, Fable 5 and Mythos 5, exclusively to US citizens. Due to the impracticality of real-time nationality verification, Anthropic shut down both models for all users, including allies. Senator Mark Warner cited General Joshua Rudd, who leads both the NSA and Cyber Command, stating that Mythos infiltrated classified systems rapidly. While these claims are unverified, Mythos's capabilities are not in dispute; it has reportedly uncovered thousands of vulnerabilities, including a 27-year-old flaw in OpenBSD. The shutdown impacts cybersecurity research, potentially hindering defenders while limiting the risk of malicious actors exploiting advanced AI. This event highlights the growing geopolitical significance of advanced AI capabilities and raises concerns about data and analytical sovereignty for nations like those in Europe, which regulate AI but lack comparable frontier models. Source: Security Affairs An In-Depth Guide to AI Get essential knowledge and practical strategies to use AI to better your security program. Learn More SC Staff Related Identity Your AI agent can’t be authenticated by a password reset email Dan Moore June 23, 2026 AI agents expose identity gaps as machine accounts outpace governance. Identity No more blind trust: Identity controls for AI agents Anne Saita June 23, 2026 Identity solutions like Cross App Access (XAA) manage AI agents by enforcing policies, scoping access and logging activity. AI/ML Anthropic updates privacy policy to require government ID for some users SC Staff June 22, 2026 The updated policy states that in certain circumstances, users may be asked to provide a scan of a government-issued passport or driver's license, along with a selfie and a facial geometry template. Get daily email updates SC Media's daily must-read of the most current and pressing daily news Business Email By clicking the Subscribe button below, you agree to SC Media Terms of Use and Privacy Policy . Subscribe You can skip this ad in 5 seconds