Prompt Injection is the "number one" security vulnerability for AI-driven applications in 2026. Because LLMs process all text as "instructional," they are easily tricked by hackers who hide rogue commands in websites, emails, or direct messages. In the world of DeFi, where AI agents manage real wealth, this can lead to "drainer" attacks and market manipulation. To stay safe, developers must use structured prompts, dual AI architectures, and always keep a human-in-the-loop for any movement of capital.