static void isa_cirrus_vga_realizefn(DeviceState *dev, Error **errp)
{
    ISADevice *isadev = ISA_DEVICE(dev);
    ISACirrusVGAState *d = ISA_CIRRUS_VGA(dev);
    VGACommonState *s = &d->cirrus_vga.vga;

    /* follow real hardware, cirrus card emulated has 4 MB video memory.
       Also accept 8 MB/16 MB for backward compatibility. */
    if (s->vram_size_mb != 4 && s->vram_size_mb != 8 &&
        s->vram_size_mb != 16) {
        error_setg(errp, "Invalid cirrus_vga ram size '%u'",
                   s->vram_size_mb);
        return;
    }
    vga_common_init(s, OBJECT(dev), true);
    cirrus_init_common(&d->cirrus_vga, OBJECT(dev), CIRRUS_ID_CLGD5430, 0,
                       isa_address_space(isadev),
                       isa_address_space_io(isadev));
    s->con = graphic_console_init(dev, 0, s->hw_ops, s);
    rom_add_vga(VGABIOS_CIRRUS_FILENAME);
    /* XXX ISA-LFB support */
    /* FIXME not qdev yet */
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.