Anthropic investigating claim of unauthorised access to Mythos AI tool

Anthropic is investigating a claim that unauthorized users accessed Claude Mythos, an advanced AI security tool that the company considers too dangerous to release publicly. The unauthorized access likely occurred through misuse of credentials by someone with legitimate access to Anthropic's systems through a third-party vendor, rather than through a traditional hack (a deliberate attempt to break into a computer system). The incident raises concerns about whether large AI companies can adequately control access to their most powerful models.