These weaknesses are dangerous because they are often easy to find, exploit, and can allow adversaries to completely take over a system, steal data, or prevent an application from working. The CWE Top 25 is a valuable community resource that can help developers, testers, and users — as well as project managers, security researchers, and educators — provide insight into the most severe and current security weaknesses.
The major difference between the 2020 and 2021 CWE Top 25 lists is the continued transition to more specific weaknesses as opposed to abstract class-level weaknesses.
The 2021 CWE Top 25 leverages NVD data from the years 2019 and 2020, which consists of approximately 32,500 CVEs that are associated with a weakness. A scoring formula is used to calculate a ranked order of weaknesses which combines the frequency that a CWE is the root cause of a vulnerability with the projected severity of its exploitation. In both cases, the frequency and severity are normalized relative to the minimum and maximum values seen.
For more detailed information including methodology, rankings, scoring, and refined mappings, visit the CWE Top 25 page.
