Incomplete Design Documentation
This vulnerability occurs when a system's design documentation is missing critical details about how the software actually works. Key omissions include unclear control flow, undefined data movement, missing system startup procedures, vague component relationships, or unexplained design decisions.
Incomplete design documentation creates a hidden risk that grows over the software's lifecycle. Developers and security reviewers can't accurately assess attack surfaces, data validation points, or trust boundaries when the intended architecture isn't clearly documented. This often leads to security controls being implemented incorrectly, inconsistently, or missed entirely during both initial development and subsequent maintenance. From a practical standpoint, this documentation gap forces teams to reverse-engineer the system's behavior, which is error-prone and time-consuming. It becomes nearly impossible to perform meaningful threat modeling, security audits, or impact analysis for changes. The result is a system where security flaws can persist undetected because no one has a complete picture of how all the pieces are supposed to fit together and interact.