Excessive data exposure in APIs is a pervasive and insidious security threat that often goes unnoticed compared to dramatic vulnerabilities like SQL injection. This issue arises when APIs return more data than necessary, including sensitive personal information (PII), which can amplify other vulnerabilities such as Broken Object Level Authorization (BOLA). Developers, in their quest for speed and convenience, might inadvertently expose internal data by not implementing explicit data filtering, often due to habits like returning whole objects or using ORMs that default to returning all fields. This can result in significant security risks, as attackers can exploit the excessive data exposure to gather sensitive information without sophisticated techniques, potentially leading to regulatory violations and reputational damage. Addressing this issue requires thorough checks across numerous API endpoints to ensure only the necessary data is returned, a task made challenging by the architectural nature of the problem. Robust API security testing and practices, such as automated checks and careful endpoint design, are crucial to mitigating such vulnerabilities and protecting against data breaches.