OpenAI Launches GPT-5.5-Cyber: Frontier AI Model for Critical Infrastructure Defense

What Is GPT-5.5-Cyber

On April 30, 2026, OpenAI CEO Sam Altman announced the rollout of GPT-5.5-Cyber, a frontier AI model purpose-built for cybersecurity. The model aims to rapidly strengthen the security of companies and critical infrastructure against growing cyber threats.

Initial Access: Critical Defenders First

GPT-5.5-Cyber is initially available only to critical cyber defenders. Altman stated that OpenAI will work with the entire ecosystem and the government to establish trusted access protocols, signaling that this is not a standard consumer or enterprise product, but a tool for protecting national security infrastructure.

Context: OpenAI's Cybersecurity Push

The launch coincides with the Pentagon awarding AI contracts to OpenAI and other major tech firms while excluding Anthropic, which refused to permit use of Claude for all lawful purposes including autonomous weapons and mass surveillance. OpenAI is capitalizing on its Pentagon relationship to advance AI-powered defense capabilities.

What's Next

GPT-5.5-Cyber is expected to support threat detection, vulnerability analysis, and automated infrastructure defense. OpenAI plans to broaden access as trusted deployment frameworks are finalized with government partners.