CWE-636 (未能安全地进行程序失效(Failing Open)) — Vulnerability Class 55

CWE-636, or Failing Open, is a critical design weakness where a system defaults to a permissive state upon encountering errors or failures. Instead of denying access or halting operations, the software inadvertently grants unauthorized users elevated privileges or exposes sensitive data. Attackers typically exploit this by triggering specific error conditions, such as malformed inputs or network timeouts, to force the application into its insecure fallback mode. This allows them to bypass authentication mechanisms or access restricted resources without valid credentials. To prevent this vulnerability, developers must implement robust error handling that defaults to a secure, deny-all posture. By ensuring that any unexpected failure results in the most restrictive security state possible, organizations can maintain integrity and confidentiality even when system components malfunction or encounter unforeseen issues.