Visa used Mythos to hunt for bugs in its own payment network, then open-sourced the harness that made it possible

Visa deployed Anthropic's Claude Mythos to detect vulnerabilities across its global payment network, which spans 200 countries and 175 million merchant locations. The AI model identified minor weaknesses and converted them into exploit chains that typically appear late in penetration testing. Following this proactive cybersecurity effort, Visa open-sourced the harness used to govern the hunt. Rajat Taneja, president of technology, detailed these developments and the company's shift away from traditional remediation metrics at VB Transform 2026.