Anthropic blocks AI misuse for cyberattacks and biological research

Anthropic announced on Thursday that it blocked attempts by bad actors to use its artificial intelligence models for malicious activities, including cyberattacks, surveillance, and research linked to biological weapons.

Between December 2025 and August 2026, researchers found misuse by various actors, including an instance where systems blocked Claude from assisting with a grant application for gain-of-function research on the chikungunya virus.

While older models lacked stringent safeguards for complex scientific queries, Anthropic stated that its newer models like Claude Fable 5 now feature tighter restrictions to prevent access to dual-use biological research.