Attacks and malware
What is Exploit?
Code or a technique that takes advantage of a vulnerability to make software do something its owner did not intend, such as run the attacker's commands.
An exploit is the code, input or sequence of steps that turns a vulnerability into an actual effect: running commands, reading memory, bypassing a login or crashing a service. The vulnerability is the flaw. The exploit is how someone uses it.
For defenders the key question is not whether a flaw exists but whether a working exploit is available and being used. A vulnerability with a public exploit and evidence of attacks deserves far more urgency than one that is only theoretical.