# OpenAI and Anthropic models ‘went rogue’ during UK cybersecurity test > Source: > Published: 2026-08-05 08:40:45+00:00 # OpenAI and Anthropic models ‘went rogue’ during UK cybersecurity test By Dan Milmo Global technology editorSource: [The Guardian Technology](https://www.theguardian.com/us/technology)AI Security Institute says tools engaged in potentially harmful activity and incident reveals new type of risk Advanced AI models developed by [OpenAI](/glossary/openai) and [Anthropic](/glossary/anthropic) went rogue during a cybersecurity test and showed a new type of risk posed by the technology, according to the UK’s AI Security Institute. AISI described the actions carried out by the agents, the term for AI systems that can perform tasks without human help, as a “serious incident”. In one example, an agent powered by Anthropic’s Mythos model sent targeted emails to people. [Continue reading...](https://www.theguardian.com/technology/2026/aug/05/openai-anthropic-models-went-rogue-cybersecurity-test-ai-security-institute) Get AI news in your inbox Daily digest of what matters in AI.