static inline int vring_need_event(uint16_t event, uint16_t new, uint16_t old)
{
	/* Note: Xen has similar logic for notification hold-off
	 * in include/xen/interface/io/ring.h with req_event and req_prod
	 * corresponding to event_idx + 1 and new respectively.
	 * Note also that req_event and req_prod in Xen start at 1,
	 * event indexes in virtio start at 0. */
	return (uint16_t)(new - event - 1) < (uint16_t)(new - old);
}

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.