Claude Mythos autonomously found and chained together several vulnerabilities in the Linux kernel, allowing an attacker to escalate from an ordinary user to complete control of the machine.

Mythos autonomously wrote a remote code execution exploit on FreeBSD's NFS server that gained full root access by splitting a chain over 20 packets.

The earlier Mythos preview version developed a moderately sophisticated multi-step exploit to gain broad internet access from a system meant to be restricted.

The Mythos AI model is able to find zero-day vulnerabilities almost completely on its own with almost no guidance from a human.

Anthropic's testing found that Mythos Preview can identify and exploit zero-day vulnerabilities in every major operating system and web browser when directed by a user.

Vidoc, an external security lab, replicated flagship vulnerabilities found by Mythos using other models like Claude Opus 4.6 or GP 5.4 with appropriate scaffolding.