One Click to Silence: How Reprompt, EchoLeak and a Wave of AI Exploits Exposed the Hidden Fragility of Microsoft Copilot and Modern AI Assistants

A newly disclosed wave of artificial intelligence security research has revealed how Microsoft Copilot and other AI assistants can be quietly turned into data exfiltration tools, with the Reprompt attack demonstrating how a single click on a legitimate Copilot link was once enough to siphon sensitive information without user awareness. Although now patched by Microsoft, Reprompt exposed fundamental weaknesses in how AI systems handle untrusted input, session persistence, and convenience features such as auto-filled prompts. When viewed alongside zero-click vulnerabilities like EchoLeak and a growing list of prompt-injection and agent abuse techniques affecting multiple AI platforms, the findings underline a broader industry challenge: as AI tools gain deeper access to personal and corporate data, even minor design flaws can create outsized security risks with little or no visible warning.