Apache Struts 2, a popular Java framework for web applications, has a history of critical security vulnerabilities, notably in its file upload mechanism, which can lead to remote code execution if exploited. The framework's vulnerability CVE-2024-53677, published in December 2024, highlights flaws that allow attackers to manipulate file upload parameters for unauthorized file placement. While Struts version 6.4.0 introduced a new file upload mechanism called ActionFileUploadInterceptor, complete mitigation is only achieved in version 7.0.0 and later, where the deprecated and vulnerable FileUploadInterceptor is fully removed. The blog post explains the mechanics of the vulnerability, how file uploads work in Struts, and offers mitigation strategies, emphasizing the need for developers to upgrade to the latest versions and refactor their file upload implementations. The post also discusses how attackers exploit the system using mass assignment attacks and recommends using tools like Dynatrace Runtime Vulnerability Analytics to detect and address such vulnerabilities.