The cyber risk posed by frontier AI is the “most immediate concern” facing the global financial system, ministers and central bank governors from the world’s largest economies were warned in a letter published Monday.

Andrew Bailey, chair of the Financial Stability Board, called on financial institutions and technology providers to “prepare for more severe scenarios involving simultaneous disruption across multiple firms or shared technology dependencies.”

The FSB was created by the G20 after the 2008 financial crisis to monitor risks that could spread across borders. Its warning follows cybersecurity evaluations at OpenAI, Anthropic, Meta and the UK’s AI Security Institute that have resulted in advanced models engaging in unauthorized activities targeting third-party systems.

Those incidents come as security agencies assess AI could make it faster and cheaper to find and exploit vulnerabilities. The FSB letter echoes a warning by Britain’s National Cyber Security Centre of increased operational risks if organizations fail to keep pace with an accelerated patching cycle.

While there has been an observable increase in the number of patches issued by companies such as Microsoft, widespread exploitation of those newly disclosed flaws has not yet been observed.