Exclusive: OpenAI, Anthropic meet with House Homeland Security behind closed doors on cyber threats

OpenAI and Anthropic held classified briefings with the House Homeland Security Committee to discuss their new cyber-capable AI models and their implications for national security. Anthropic delayed the release of its Mythos Preview model due to security risks, while OpenAI adopted a tiered approach for its GPT-5.4-Cyber model. Both companies are collaborating with federal agencies to assess the models' cybersecurity risks.