pdf14_compute_group_device_int_rect(const gs_matrix *ctm,
                                    const gs_rect *pbbox, gs_int_rect *rect)
{
    gs_rect dev_bbox;
    int code;

    code = gs_bbox_transform(pbbox, ctm, &dev_bbox);
    if (code < 0)
        return code;
    rect->p.x = (int)floor(dev_bbox.p.x);
    rect->p.y = (int)floor(dev_bbox.p.y);
    rect->q.x = (int)ceil(dev_bbox.q.x);
    rect->q.y = (int)ceil(dev_bbox.q.y);
    return 0;
}

The product dereferences a pointer that it expects to be valid but is NULL.