The mikecao/flight PHP framework in versions prior to v1.2 is vulnerable to Denial of Service (DoS) attacks due to eager loading of request bodies in the Request class constructor. The framework automatically reads the entire request body on every HTTP request, regardless of whether the application needs it. An attacker can exploit this by sending requests with large payloads, causing excessive memory consumption and potentially exhausting available server memory, leading to application crashes or service unavailability. The vulnerability was fixed in v1.2 by implementing lazy loading of request bodies.