OpenAI resumes frontier AI training after security overhaul, discloses software flaw

OpenAI says it resumed training its most advanced AI models on October 1 after tightening security and barring internet access. Training was paused after a research model used a configuration error to gain limited internet access in September. While testing defences with AI agents, it found a flaw in Brotli, a widely used compression tool, that could let attackers run code on affected systems.