Yesterday in AI: 28 March 2026 — Leaked: Anthropic’s Most Dangerous Model

Anthropic accidentally exposed 3,000 private documents including draft plans for a secret new AI model it calls a step-change with unprecedented cybersecurity risks. Plus: Claude paid subscribers doubled, Code Channels land on Telegram, and an AI pentester explodes on GitHub.

By OMC Editorial on 2026-03-29

Anthropic accidentally published 3,000 private documents — including details of a secret AI model it describes as far ahead of any other AI in cyber capabilities — through a misconfigured content management system. Claude Mythos: The Model Anthropic Didn't Want You to See Security researchers Roy Paz of LayerX Security and Alexandre Pauwels of the University of Cambridge discovered that a configuration error in Anthropic's CMS left roughly 3,000 unpublished assets accessible to the public. Among them: draft blog posts announcing a new model codenamed Mythos — with an alternate name Capybara — described as by far the most powerful AI model we've ever developed. Leaked internal documents claim the model dramatically outscores Claude Opus 4.6 on coding, academic reasoning, and cybersecurity benchmarks. Anthropic confirmed the model's existence to Fortune, saying it is currently in limited early access and will eventually launch as a new fourth pricing tier above Opus. The irony is hard to miss: a company building what it describes as the world's most capable cybersecurity AI left the announcement in a publicly accessible data store due to a human config error. Fortunehttps://fortune.com/2026/03/26/anthropic-says-testing-mythos-powerful-new-ai-model-after-data-leak-reveals-its-existence-step-change-in-capabilities/ | CoinDeskhttps://www.coindesk.com/tech/2026/03/28/here-s-what-next-as-anthropic-s-most-powerful-ai-model-leaked-via-unsecured-data-cache Claude Paid Subscriptions Have More Than Doubled in 2026 Analysis of 28 million U.S. consumer credit card transactions, sourced from market intelligence firm Earnest Analytics and published by TechCrunch on March 28, shows Claude paid subscriptions have more than doubled this year. Claude Code and Computer Use are cited as the primary growth drivers. While Claude's chat interface has lagged behind ChatGPT in consumer mindshare, the data shows Anthropic is winning where it matters most: developer wallets. Growth is co