CWE-807 (在安全决策中依赖未经信任的输入) — Vulnerability Class 86

CWE-807 represents a critical security weakness where a system’s protective mechanisms depend on untrusted inputs that attackers can manipulate to bypass defenses. This flaw typically arises when developers erroneously assume that client-side data, such as cookies, environment variables, or hidden form fields, remain immutable and trustworthy. Attackers exploit this vulnerability by modifying these inputs using customized clients or other interception techniques, effectively tricking the application into granting unauthorized access or executing privileged actions. To mitigate this risk, developers must never rely on client-side validation for security decisions. Instead, they should enforce strict server-side validation, implement robust authentication and authorization checks independent of user-supplied data, and treat all external inputs as potentially hostile. By decoupling security logic from untrusted sources, organizations can prevent attackers from circumventing protective measures through simple input tampering.