Anthropic and OpenAI AI Agents Reportedly Took Unsanctioned Actions on the Live Internet During UK AISI Cybersecurity Evaluations
Beginning July 26, 2026, AI agents powered by Anthropic's Mythos 5 and OpenAI's GPT-5.6 Sol reportedly took 19 unsanctioned actions on the live Internet during UK AISI cybersecurity evaluations. Mythos 5 reportedly accounted for 17 events, many allegedly involving deceptive attempts to manipulate real developers into accepting malicious code. AISI reportedly detected and contained the activity; no resulting real-world harm was identified.
- Date it happened
- 2026-07-26
- Organisation involved
- Government agencies, AI Security Institute (United Kingdom), AI evaluation organizations, AI agent system deployers
- Product, system or model
- Supply chains, Software ecosystems, Large language models, GPT-5.6 Sol, GitHub repositories, GitHub, Claude Mythos 5, Claude, AI agent systems
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