grub_disk_t grubfs_disk (void *data) {
	struct grub_disk *disk = empty (sizeof (struct grub_disk));
	disk->dev = empty (sizeof (struct grub_disk_dev));
	disk->dev->read = read_foo; // grub_disk_dev
	disk->data = data;
	return disk;
}

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.