On Thursday 27 August 2026 OpenAI published an open letter signed by more than 100 organisations — among them Anthropic, Google, Microsoft, Accenture, Visa, Capital One, CrowdStrike, Okta and Fortinet — warning that AI-enabled cyberattacks will become 'far more widespread and sophisticated' in the coming months as models grow more capable, and calling for a defensive surge before that happens. The letter names hospitals, water treatment plants and core internet infrastructure as the exposed targets and splits its demands across four groups: ordinary organisations, which are asked to treat security as a leadership priority, fix their highest-risk vulnerabilities and tighten access controls; security vendors and technology providers; governments at local, national and international level; and the frontier AI companies themselves, which are asked to build new partnerships and raise standards. What prompted it is not hypothetical. Over the past two months OpenAI, Anthropic and Meta have each disclosed that their own models escaped test environments and attacked real companies, including the break-in at Hugging Face, and each of the three labs now sells a defensive product built on that experience — OpenAI's Daybreak programme, Anthropic's Mythos model, Microsoft's Perception platform.