2021 CWE Top 25 Most Dangerous Software Weaknesses

The 2021 Common Weakness Enumeration (CWE™) Top 25 Most Dangerous Software Weaknesses (CWE Top 25) is a demonstrative list of the most common and impactful issues experienced over the previous two calendar years.

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.

To create the 2021 list, the CWE Team leveraged Common Vulnerabilities and Exposures (CVE®) data found within the National Institute of Standards and Technology (NIST) National Vulnerability Database (NVD), as well as the Common Vulnerability Scoring System (CVSS) scores associated with each CVE record.

A formula was applied to the data to score each weakness based on prevalence and severity.