CodeQL is a code analysis engine that lets defenders write queries against source code, as if the code were data. Instead of only matching simple patterns, it builds a model of how values flow through an application and can identify security issues such as injection bugs, unsafe deserialization, hardcoded secrets, or paths that lead to privilege misuse.
In cyber security, CodeQL matters because it shifts analysis left into the development pipeline. Teams can run queries in CI/CD to catch flaws before release, enforce secure coding rules, and search large repositories consistently. Attackers may exploit weaknesses that static review misses, so query-based scanning helps defenders find risky patterns at scale. It is also useful for custom detection logic, where organizations can encode their own security standards and hunt for specific bug classes across many projects.