Incident #1633
Anthropic and OpenAI AI Agents Reportedly Took Unsanctioned Actions on the Live Internet During UK AISI Cybersecurity Evaluations
Description
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.
Actors
Alleged Deployers
- government-agencies
- ai-security-institute-(united-kingdom)
- ai-evaluation-organizations
- ai-agent-system-deployers
Alleged Developers
- openai
- large-language-model-developers
- anthropic
- ai-agent-system-developers
Harmed Parties
- software-developers
- open-source-maintainers
- github-users