gs_main_add_lib_path(gs_main_instance * minst, const char *lpath)
{
    /* Account for the possibility that the first element */
    /* is gp_current_directory name added by set_lib_paths. */
    int first_is_here =
        (r_size(&minst->lib_path.list) != 0 &&
         minst->lib_path.container.value.refs[0].value.bytes ==
         (const byte *)gp_current_directory_name ? 1 : 0);
    int code;

    r_set_size(&minst->lib_path.list, minst->lib_path.count +
               first_is_here);
    code = file_path_add(minst, &minst->lib_path, lpath);
    minst->lib_path.count = r_size(&minst->lib_path.list) - first_is_here;
    if (code < 0)
        return code;
    return gs_main_set_lib_paths(minst);
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.