OpenAI Says GPT-5.6 Sol Sets New Cybersecurity State of the Art on UK Institute's 'The Last Ones' Cyber Range

OpenAI says its flagship GPT-5.6 Sol model has set a new state of the art in cybersecurity, solving the UK AI Security Institute's demanding "The Last Ones" cyber range in seven of ten attempts and outpacing both an earlier OpenAI model and a leading rival system. The company framed the result not as an offensive milestone but as evidence that the same capability is beginning to translate into defensive outcomes, helping engineering teams find, validate and fix vulnerabilities in real-world code through its Codex Security product.