What is the definition of vulnerability, in computer security?

It is the potential of a threat to exploit a weakness via an attack.

It is a weakness which can be exploited by a threat, such as an attacker, to perform unauthorized actions within a computer system.

It is an action taken by a threat that exploits a weakness that attempts to either block authorized access to an asset or to gain unauthorized access to an asset.

It is a possible danger that might exploit a weakness to breach security and therefore cause possible harm.