Which of the following is NOT a common type of software vulnerability?

Firewall bypass is considered not a common type of software vulnerability because it refers specifically to evading security measures, rather than an inherent flaw in software itself. Common software vulnerabilities typically involve issues that stem from how software processes data or handles user input, leading to unintended behavior or security weaknesses.

In contrast, buffer overflow, SQL injection, and Cross-Site Scripting (XSS) are all well-documented vulnerabilities that arise from the way software handles memory, interacts with databases, or processes web content, respectively. Each of these vulnerabilities represents a specific type of exploit that can occur due to coding errors or oversights in input validation, making them key concerns in secure software design.

Understanding the distinction helps in developing secure software practices, such as proper input validation and secure coding techniques, to prevent malicious exploitation.