void vnc_write(VncState *vs, const void *data, size_t len)
{
    buffer_reserve(&vs->output, len);

    if (vs->csock != -1 && buffer_empty(&vs->output)) {
        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);
    }

    buffer_append(&vs->output, data, len);
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.