OpenAI’s Startup Fund has made its first cybersecurity investment, co-leading a $43 million Series A round in Adaptive Security — a startup focused on simulating and preparing for AI-enabled cyber threats. The move signals OpenAI’s growing interest in proactive AI safety and defense infrastructure as generative AI accelerates real-world adoption.

Adaptive Security’s platform uses AI to mimic sophisticated cyberattacks, helping enterprises test their digital resilience and train against evolving threats. Its software can simulate breaches, malware infections, social engineering exploits, and multi-step attack vectors, giving security teams realistic, automated scenarios to train on.

The $43M round was co-led by OpenAI Startup Fund and existing investors, with participation from security-focused VCs. The company plans to use the funds to expand R&D, scale operations, and partner with large enterprises and government agencies concerned about emerging AI-driven attack surfaces.

This marks a strategic expansion for OpenAI’s investment arm, which has primarily backed AI model developers and tooling startups. By supporting a defensive AI platform, OpenAI signals its recognition that offensive AI capabilities must be met with equally advanced protections.

The funding comes amid increasing warnings from security researchers about generative AI’s potential misuse — from phishing automation to autonomous exploitation. With this investment, Adaptive Security aims to become a category leader in AI-native cybersecurity.