OpenAI published an open letter, "A call for collective action on cyber defense," signed on that page by OpenAI, Anthropic, Google, Microsoft, AWS and a long listed set of other firms.

The letter says there is a limited window to strengthen cyber defences; that in the coming months AI-enabled cyber attacks will become far more widespread and sophisticated as models become more capable; and that hospitals, water treatment plants and internet infrastructure are at risk. It argues status-quo security will not be enough, and calls on organisations, cybersecurity companies and governments to put cyber-capable AI in defenders' hands, starting with essential services.

Dated 27 August 2026 in contemporaneous reporting; the letter page itself does not print a date.