Software vulnerabilities are regard as the most critical vulnerabilities due to its impact and availability as compared to hardware and network vulnerabilities. Throughout the years from the first appearance of software vulnerabilities in late 80s until today, there are many identified and classified software vulnerabilities such as the well-known buffer overflow, scripting and SQL command. We studied on those known software vulnerabilities, compared the criticality, impact and significant of the vulnerabilities, and further predicted the trend of the vulnerabilities and proposed the focus area based on the comparative studies. The result shows that C overflow vulnerabilities will continue to persist despite losing its dominance in terms of numbers of availability and exploitation. However, the impact of exploiting the C overflow vulnerabilities is still regard as the most critical as compare to others. Therefore, C overflow vulnerabilities will prevail again and continues its domination as it did for the past two decades.