Anthropic Accidental Leak Next-Gen Model "Claude Mythos": A New Level Beyond Opus, Network Security Capability "Far Beyond All Existing AI"

According to 1M AI News's monitoring, Anthropic is currently testing a new model named "Claude Mythos." Due to a content management system configuration error, an unpublished blog draft was stored in a publicly searchable database, inadvertently exposing the existence of this model. Anthropic later confirmed this model, describing it as representing a "step change in capability" and as "the most powerful model we have built to date."

The leaked draft revealed that Mythos is a new model tier positioned above the Opus series. The draft stated that "compared to the previous leading model, Claude Opus 4.6, this model achieved significantly higher scores in tests related to software programming, academic reasoning, and cybersecurity." The draft also mentioned the codename "Capybara," which points to the same underlying model as Mythos.

Anthropic is particularly cautious about the cybersecurity capabilities of this model. The draft mentioned that it is currently "far ahead of any other AI model in terms of cybersecurity capabilities" and "heralds an upcoming wave of models whose exploit capabilities will far outpace defenders' response times." Therefore, Anthropic has adopted a slower-than-usual release strategy: initially opening up to a small group of early customers, focusing on cybersecurity defense scenarios to help organizations secure their code repositories before the rise of AI-driven attacks. The operational costs of this model are extremely high, and it will not be made available to the public in the short term.

This leak stemmed from a "human error" in Anthropic's external CMS tool, leading to the exposure of nearly 3000 unpublished assets (including blog drafts, images, and PDFs) stored openly in an unencrypted database. The leak was independently discovered by Cambridge University cybersecurity researcher Alexandre Pauwels and LayerX Security's Senior AI Security Researcher Roy Paz. The leaked content also includes details about an upcoming European Enterprise CEO Summit hosted by Anthropic in the UK, with CEO Dario Amodei in attendance at an 18th-century country estate hotel.

Anthropic's spokesperson stated: "We are developing a universal model that has made significant advancements in reasoning, programming, and cybersecurity. Given the strength of its capabilities, we will be very cautious in its release."