The Guardian view on Anthropic’s Claude Mythos: when AI finds every flaw, who controls the internet? | Editorial

Tech can scale cyber-attacks and defences alike, raising questions about private power, public risk and the future of a shared internet

Anthropic announced its latest AI model, https://www.theguardian.com/technology/2026/apr/08/anthropic-ai-cybersecurity-software">Claude Mythos, this month but said it would not be released publicly, because it turns computers into crime scenes.

The company claimed that it could find previously unknown “zero-day” flaws, exploit them and, in principle, link these weaknesses in order to take over https://red.anthropic.com/2026/mythos-preview/">major operating systems and web browsers.

Mythos did so autonomously, writing code and obtaining privileges.

The implications are significant.

It’s like a burglar being able to target any building, get inside, unlock every door and empty every safe.

The Silicon Valley company has so far named 40 https://www.bbc.co.uk/news/articles/crk1py1jgzko">organisations as partners under Project Glasswing to help mount a defence – asking them to “patch” vulnerabilities before hackers get a chance to exploit them.

All are American, sitting at the heart of the US-led digital system.

Anthropic shared Mythos with only Britain outside the US, allowing the AI Security Institute to test frontier models.

After seeing it up close, British ministers https://www.gov.uk/government/publications/ai-cyber-threats-open-letter-to-business-leaders/ai-cyber-threats-open-letter-to-business-leaders-html">warned: AI is about to make cyber-attacks much easier and faster, and most businesses are not ready.

Banks in https://www.reuters.com/business/finance/anthropic-plans-provide-mythos-access-european-banks-soon-sources-say-2026-04-21/">Europe are likely to test it next.