cgichk vulnerability scanner

The source code :

...
lowerstr(n);
...
res = (char*)strstr(h, n);
free(h);
free(n);
return res;

You can see that res point to a freed memory ,and could
not
use to get anyinfomation ,OFFCOURSE, the usage of the
program is okay for only check the existence of the
given key string in the given buff