US Export Order Forces Anthropic to Disable Fable 5 and Mythos 5
Anthropic pulled its cybersecurity-focused AI models Fable 5 and Mythos 5 worldwide after receiving a U.S. government export-control directive that barred access by foreign nationals, including people inside the United States and Anthropic employees. The company said the unpublished order invoked national security authorities and may mark the first known use of export powers to restrict AI models rather than chips or other hardware, with reporting indicating Anthropic had about 90 minutes to take the systems offline.
Anthropic said officials claimed the models could be jailbroken to review code and help fix software flaws, but the company disputed both the technical basis and the severity of the concern. It said the evidence was delivered only verbally, the behavior was narrow and previously known, and similar capabilities exist in other public models, including OpenAI GPT-5.5. Anthropic warned that applying this standard broadly could disrupt frontier AI deployments across the industry, while reports identified the White House, the Commerce Department, and Amazon as involved in the decision process as the company works to restore access.
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How this story unfolded
15 events from the most recent confirmed update back to the earliest known activity.
OpenAI privately releases cybersecurity-focused model
Ars Technica reported that OpenAI privately released a cybersecurity-focused model in mid-April 2026 and broadened its cybersecurity strategy. The development was cited by experts arguing that restricting Anthropic alone would not stop similar AI cyber capabilities from emerging elsewhere.
European and Canadian officials protest Anthropic model export cutoff
Following the U.S. export restrictions on Anthropic’s Fable 5 and Mythos 5 models, officials in Europe, Canada, and the UK publicly warned that sudden loss of access to frontier AI created a strategic vulnerability for allied governments and projects. The reactions framed frontier AI access as critical infrastructure and highlighted concerns about dependence on U.S. providers.
Members of Congress question Anthropic export-control order
Lawmakers including Sen. Angus King, Rep. Bennie Thompson, Sen. Mark Warner, and House Homeland Security Chairman Andrew Garbarino publicly reacted to the Trump administration’s export controls on Anthropic’s Fable 5 and Mythos 5 models, with several expressing skepticism about the lack of clear justification and the appearance of a politically driven process. Some Republicans withheld judgment pending more information from the administration.
More than 100 cyber leaders urge easing Anthropic model restrictions
More than 100 cybersecurity executives and experts urged the Trump administration to reverse or ease export-control restrictions blocking foreign nationals from using Anthropic’s Fable 5 and Mythos 5 models. They argued the limits could weaken U.S. cyber defense more than they impede adversaries and said Anthropic’s models are not uniquely capable compared with other frontier systems.
Amazon raises Anthropic dispute with Treasury Secretary Bessent
Axios reported that Amazon raised concerns about the Anthropic export-control dispute to Treasury Secretary Scott Bessent. The report also said follow-up meetings were scheduled with the Commerce Department, the CIA, and White House science adviser Michael Kratsios as the administration and company sought to resolve the standoff.
76 cybersecurity experts urge U.S. to lift Anthropic model ban
A coalition of 76 cybersecurity experts published an open letter urging the U.S. government to rescind the export-control order on Anthropic’s Fable and Mythos models. The signatories argued the restriction harms defenders by denying them advanced tools for vulnerability discovery and remediation and called for transparent, scientifically grounded AI regulation.
Anthropic publicly disputes the directive's technical basis
Anthropic said it complied with the order but challenged the government's rationale, arguing the cited jailbreak was narrow, previously known, and reproducible on other public models such as OpenAI's GPT-5.5. The company said it is working to restore access and warned that applying this standard broadly could disrupt frontier AI deployments across the industry.
White House talks with Anthropic end without lifting model restrictions
Anthropic met with White House officials in Washington, DC, on 2026-06-15 to discuss the export controls on Fable 5, but the talks ended without the Trump administration lifting the restrictions. The outcome showed continued disagreement over the model's jailbreak risk and national security implications.
Anthropic disables Fable 5 and Mythos 5 worldwide
After receiving the directive, Anthropic globally disabled access to its cybersecurity-focused Fable 5 and Mythos 5 models. ZDNET reported, citing Axios, that Anthropic had about 90 minutes on Friday to take the models offline.
U.S. government issues export directive targeting Anthropic models
The U.S. government sent Anthropic an unpublished export-control directive invoking national security authorities to bar foreign nationals, including some people inside the United States and Anthropic employees, from accessing Fable 5 and Mythos 5. Anthropic said the government believed the models could be jailbroken for cyber use, but provided only verbal evidence.
Anthropic CEO publishes essay backing authority to block unsafe AI
Shortly before the export-control action, CEO Dario Amodei published a policy essay supporting government authority to block unsafe AI deployments, though Anthropic later argued such power should be exercised transparently and on a technical basis.
Defense Department labels Anthropic a supply chain risk
In February 2026, Defense Secretary Pete Hegseth designated Anthropic a supply chain risk following failed military contract negotiations, according to The Record.
Anthropic sends technical staff to Washington for White House talks
Senior technical staff from Anthropic traveled to Washington, D.C. to meet White House officials over the dispute that led to the Fable and Mythos models being taken offline. Axios also reported the company had been holding virtual meetings with administration officials since the administration’s initial outreach on Friday as both sides sought a quick resolution.
Trump reportedly orders agencies to stop using Anthropic AI
According to the new report, Trump had already directed federal agencies in February 2026 to stop using Anthropic’s AI. The move was described as part of broader tensions between Anthropic and the administration before the later export-control action targeting Fable 5 and Mythos 5.
Commerce Department sends Anthropic June 12 suspension letter
Anthropic said it received a June 12 letter from the U.S. Commerce Department ordering it to suspend access to its Fable 5 and Mythos 5 models for all foreign nationals. According to the report, this effectively triggered a global shutdown because Anthropic could not reliably separate users by nationality.
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Sources
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"Dangerous" AI models are coming no matter what
arstechnica.com
Open sourceUS pulls the 'kill-switch' on Anthropic's Fable 5 AI models, sending global allies scrambling - European and Canadian leaders alarm allies over sudden export bans | Tom's Hardware
tomshardware.com
Open sourceU.S. Commerce Dept Imposes Export Controls on Anthropic's Claude Mythos 5 and Fable 5
cybersecuritynews.com
Open sourceAnthropic Pushes Back Against US Order Restricting Claude Fable 5, Backed by Cybersecurity Experts - gHacks Tech News
ghacks.net
Open source“단일 AI 모델=새로운 단일 장애 지점”…앤트로픽 접근 차단이 던진 경고 | CIO
cio.com
Open sourceMythos Shutdown Contains a Message: Don't Wait for Mythos
bankinfosecurity.com
Open sourceAnthropic flies staff to DC to clean up White House fight
axios.com
Open sourceAmazon security research reportedly led to the White House’s Anthropic Fable ban | The Verge
theverge.com
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U.S. Weighs CISA Use of Anthropic Mythos as Export Controls Cut Foreign Access
Senior U.S. officials are considering giving the Cybersecurity and Infrastructure Security Agency access to Anthropic’s **Mythos** model so it can coordinate vulnerability scanning across federal civilian agencies, with a focus on finding public-facing weaknesses and other security flaws on government networks. The discussions come as agencies seek clearer direction on how advanced AI models will be used in cyber defense, following a White House push for stronger network security measures and CISA’s role in developing guidance and an AI vulnerability clearinghouse. CISA officials have stressed that AI could accelerate detection and prioritization, but would not replace remediation work, infrastructure modernization, or the reduction of technical debt. At the same time, the Trump administration has tightened control over Anthropic’s most advanced systems by placing **Mythos 5** and **Fable 5** under Commerce Department export restrictions, requiring licenses for export, re-export, or transfer to foreign persons. The move reportedly followed national security concerns after claims that Mythos had been jailbroken, and Anthropic said it suspended customer access to the affected models to comply while disputing the government’s rationale. The parallel actions highlight a split U.S. approach to frontier AI: expanding potential domestic cybersecurity use inside government while restricting broader access to the company’s most powerful models.
Jun 18, 2026
US Government Blacklisting of Anthropic Drives Agency AI Model Swaps and Lawsuits
The US State Department replaced Anthropic’s **Claude Sonnet 4.5** with OpenAI’s **GPT-4.1** as the underlying model for its internal chatbot, *StateChat*, after a Feb. 27 presidential directive ordering federal agencies to remove Anthropic tools. Internal documentation cited by Nextgov/FCW indicates Claude models were removed from the department’s enterprise generative AI platform and that users of Claude-based custom GPT configurations were instructed to transition to non-Anthropic, government-approved models; the change also reset *StateChat*’s available knowledge base to older data (reported as reverting to May 2024 from a more recent June 2025 corpus used previously). Anthropic responded by filing lawsuits challenging the government’s actions, with reporting indicating the dispute is tied to a **supply chain risk designation** and broader claims about the company’s policy positions. Ars Technica reported that Anthropic CEO **Dario Amodei** has publicly opposed certain government uses of AI—particularly **mass domestic surveillance** and fully **autonomous lethal weapons**—while stating support for lawful foreign intelligence and counterintelligence missions; the outlet also noted a supporting brief from technical staff at **Google** (an Anthropic investor) and **OpenAI**, arguing the designation could chill industry debate and harm US innovation competitiveness. Separately, Reuters and Nextgov/FCW reporting described similar directives across multiple agencies to switch from Claude to ChatGPT following the governmentwide move away from Anthropic technology.
Apr 16, 2026
Unauthorized Users Access Anthropic’s Restricted Claude Mythos Cyber Model
Anthropic said it is investigating reports that unauthorized users accessed its unreleased **Claude Mythos Preview** model, a cybersecurity-focused system the company had restricted under **Project Glasswing** because it considered the model too dangerous for public release. Mythos was described as capable of autonomously finding high-severity vulnerabilities, chaining Linux kernel flaws into working exploits, uncovering long-lived bugs such as a 27-year-old OpenBSD issue, and completing complex multi-step attack simulations. Anthropic had provided limited access to selected organizations and pledged safeguards, usage credits, and coordinated defensive support to help security teams use the model for vulnerability discovery and remediation rather than offensive activity. Reports said the unauthorized access stemmed from a third-party contractor environment and a broader chain of security failures, including alleged clues exposed through the **Mercor** breach and a **LiteLLM**-linked supply-chain compromise. Bloomberg and follow-on coverage said a private Discord group may have used contractor access and educated guesses about the model’s location to reach Mythos, while Anthropic said it had no evidence of misuse beyond the third party’s IT environment. Separate unverified claims circulating online alleged that threat actor **ShinyHunters** was offering Anthropic-related Mythos data and internal documents for sale, adding to concerns over whether frontier AI systems built for defensive cyber research can be adequately secured against leakage and abuse.
May 6, 2026