A: Root Cause Analysis: Looking at the given vulnerable code line and its context, the CWE-787 (out-of-bounds write) vulnerability exists in the code because the `strncpy` function is used incorrectly. The second argument of `strncpy` should be the maximum number of characters to copy, but in this case, `sizeof(szFileName) - 5` is used, which is not the correct way to specify the maximum number of characters to copy. This can lead to potential buffer overflow issues if the length of `pszFileName` is greater than `sizeof(szFileName) - 5`, resulting in an out-of-bounds write vulnerability, which is CWE-787.