The CWE Top 25 is MITRE’s annual list of the most common and dangerous software weakness types. CWE stands for Common Weakness Enumeration, a catalog of bug classes such as SQL injection, cross-site scripting, buffer overflows, weak authentication, and improper input validation. Unlike a CVE, which identifies a specific vulnerability in a product, a CWE describes the underlying flaw pattern that can appear across many codebases.
It matters because attackers often reuse the same weakness classes at scale. If a web app accepts unsafe input, exposes memory-unsafe code, or fails to control access properly, the same design error can create many exploitable paths. Defenders use the Top 25 to prioritize secure coding rules, code review, testing, and remediation training. It is especially useful for prevention: parameterized queries, output encoding, strict validation, least privilege, and memory-safe languages directly reduce the weakness families most likely to lead to real breaches.