Over 100 companies, including OpenAI, Anthropic, Google and Microsoft, sign an open letter on AI-enabled cyberattacks

On 27 August 2026 more than a hundred companies signed an open letter urging joint public and private action against AI-enabled cyber threats. Signatories include OpenAI, Anthropic, Google and Microsoft alongside security firms such as CrowdStrike, Okta and Fortinet, plus financial institutions and internet-infrastructure operators. The letter argues AI-enabled attacks will become far more widespread as models get more capable, singles out hospitals, water treatment and other critical infrastructure, and says defenders have a window measured in months to adopt new defensive measures.

What it means When the labs shipping the capability and the vendors defending against it sign the same letter, the hardening work stops being optional for anyone running infrastructure.