Deceptive patterns are design practices embedded in digital platforms to manipulate users, representing a widespread and long-standing issue in the web and mobile software development industry. Legislative actions highlight the urgency of globally regulating deceptive patterns. However, despite advancements in detection tools, a significant gap exists in assessing deceptive pattern risks. In this study, we introduce a comprehensive approach involving the interactions between the Adversary, Watchdog (e.g., detection tools), and Challengers (e.g., users) to formalize and decode deceptive pattern threats. Based on this, we propose a quantitative risk assessment system. Representative cases are analyzed to showcase the practicability of the proposed risk scoring system, emphasizing the importance of involving human factors in deceptive pattern risk assessment.