Anthropic's Mythos: When the World's Most Dangerous AI Becomes a Defender's Best Tool
Anthropic briefly exposed a toggle for "Claude Mythos" in the public version of Claude Code last week, then quietly pulled it offline. The model identifier is claude-mythos-1-preview, and its existence in the wild — even for a few hours — confirms what security researchers have been suspecting: Anthropic is preparing to let regular users access a model that can autonomously develop full exploit chains, chain zero-days across operating systems, and bypass KASLR protections on hardened kernels like OpenBSD. The exploits aren't toy-level either. In Anthropic's own testing, Mythos wrote a browser exploit that chained four vulnerabilities together, including a complex JIT heap spray that escaped both renderer and OS sandboxes. On FreeBSD, it split a 20-gadget ROP chain over multiple packets to grant root access to unauthenticated users. The oldest bug it found was 27 years old — in OpenBSD, of all things. The thing that makes this story worth paying attention to isn'...