CWE-501 (违背信任边界) — Vulnerability Class 19

CWE-501 represents a critical trust boundary violation where software improperly mixes trusted and untrusted data within the same structure or message. This weakness occurs when a program fails to distinguish between data originating from secure internal sources and potentially malicious external inputs. Attackers typically exploit this flaw by injecting untrusted data into contexts expecting only trusted information, thereby bypassing security controls or triggering unintended behaviors. To prevent such vulnerabilities, developers must strictly enforce validation logic at every trust boundary. This involves rigorously sanitizing all external inputs before they enter the system’s core logic and ensuring that data structures clearly separate trusted internal state from untrusted external data. By maintaining clear separation and validating data crossings, developers can ensure that only safe, verified information influences critical application processes.