What Is a Vulnerability?
Sometimes, vulnerabilities are straightforward flaws due to bad design. For example, the Tacoma Narrows Bridge in the state of Washington was built in 1940 and collapsed later that year in a 40-mph wind due to poor construction. No lives were lost (the suspension bridge underwent reconstruction in 1950 and is still standing).
Sometimes, though, vulnerabilities are part of the actual design. Consider door locks. A door lock is not flawed because it can be unlocked. There’s no inherent design flaw in how the pins and tumblers are precision-crafted and laid out. The issue is not that the structure is poor, but their structure and precision design provide a consistent way for would-be thieves to know how to pick them. (For more information on locksport, one good organization is TOOOL).