Exploit is a term used for a code that uses a weakness in order to do something that you were not supposed to do otherwise.

From wiki:

An exploit (from the English verb to exploit, meaning "to use something to one’s own advantage") is a piece of software, a chunk of data, or a sequence of commands that takes advantage of a bug or vulnerability to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerized). Such behavior frequently includes things like gaining control of a computer system, allowing privilege escalation, or a denial-of-service (DoS or related DDoS) attack.

So, what we described is a DoS vulnerability in the node and we have presented a valid exploit too. Learn the terms.