static float *get_window(vorb *f, int len)
{
    len <<= 1;
    if (len == f->blocksize_0) return f->window[0];
    if (len == f->blocksize_1) return f->window[1];
   assert(0);
    return NULL;
 }

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.