flaw

Definition: In network security, a vulnerability refers to any flaw or weakness in the network defense that could be exploited to gain unauthorized access to, damage or otherwise affect the network.

Definition: A flaw can refer to either a Bug, in the case of a flaw in the actual code of an application or operating system, or a flaw could be a vulnerability, in the case of a weakness or oversight

Definition: In computer technology, a bug is a coding error in a computer program. After a product is released or during public beta testing, bugs are still apt to be discovered. When this occurs, users have to either find a