Anthropic dominates Cisco’s LLM Security Leaderboard

Eight of the top ten spots are held by Anthropic’s models, with Claude Opus 4.5 in first place, followed by Sonnet 4.5 and Haiku 4.5. Cisco evaluated models’ resilience to multi-step attacks simulating real hacker behavior.

OpenAI’s GPT-5.2 and GPT 5 Nano placed seventh and ninth. Models from Mistral, DeepSeek, Cohere, and xAI ranked lower. Cisco notes that over 80% of companies plan to deploy AI agents, but only a third are prepared to protect enterprise data.