Unauthorized Users Breach Anthropic's Mythos AI Model via Third-Party Vendor Environment

Summary

Unauthorized users — members of a private Discord channel focused on unreleased AI models — gained access to Anthropic's Mythos AI model through a third-party vendor environment, according to a Bloomberg report published April 21, 2026 and widely covered by April 22. The users successfully employed multiple strategies to breach the system and have been regularly using Mythos since gaining access. Anthropic confirmed the investigation: "We're investigating a report claiming unauthorised access to