Why CI Pipelines Need Both SAST and SCA Security Scanners

Security scanning in CI/CD pipelines falls into two distinct categories: Static Application Security Testing (SAST), which analyzes code written by developers, and Software Composition Analysis (SCA), which checks imported open-source dependencies against known vulnerability databases. SAST detects flaws like SQL injection, hardcoded credentials, and weak cryptography directly in source code, while SCA identifies vulnerable package versions such as a lodash or jsonwebtoken library with a known CVE. The two tools have nearly complementary blind spots — SAST cannot detect vulnerabilities in third-party libraries, while SCA cannot find security bugs in custom-written code. A real-world Node.js application, for example, could simultaneously carry a NoSQL injection flaw invisible to SCA and a vulnerable JWT library undetectable by SAST. Running both scanners in parallel within a CI pipeline is therefore recommended to close both attack vectors effectively.