CWE-131 (缓冲区大小计算不正确) — Vulnerability Class 109

CWE-131 represents a critical logic error where software fails to accurately determine the necessary memory allocation size for a buffer. This miscalculation typically stems from using incorrect data types, ignoring header overhead, or neglecting null terminators during size computations. Attackers exploit this vulnerability by crafting inputs that exceed the allocated memory space, triggering a buffer overflow. This overflow allows malicious actors to overwrite adjacent memory, potentially executing arbitrary code, crashing the application, or gaining unauthorized system access. To prevent such exploits, developers must rigorously validate input lengths and employ safe, bounds-checking functions like strncpy or snprintf instead of unsafe alternatives. Additionally, utilizing static analysis tools and conducting thorough code reviews can help identify arithmetic errors in memory allocation logic before deployment, ensuring that buffer sizes accurately reflect the actual data requirements.