CWE-134 (使用外部控制的格式字符串) — Vulnerability Class 138

CWE-134 represents a critical input validation weakness where software utilizes functions accepting format strings, such as printf, with data originating from an untrusted external source. Attackers typically exploit this vulnerability by injecting malicious format specifiers, like %x or %n, into the input stream. This manipulation allows them to read sensitive memory contents, causing denial of service, or write arbitrary data to memory, potentially leading to remote code execution and full system compromise. To mitigate this risk, developers must strictly avoid passing user-controlled data directly as the format string argument. Instead, they should use literal format strings and pass user input as subsequent arguments. Additionally, implementing rigorous input validation and employing static analysis tools can help detect these dangerous patterns early in the development lifecycle, ensuring that external data is never interpreted as executable code logic.