How to Block Vulnerable Docker Images in CI/CD Pipelines Using Trivy

Security vulnerabilities in Docker images can silently reach production when CI/CD pipelines lack a dedicated scanning step. Trivy, an open-source security scanner by Aqua Security, can inspect container images for known vulnerabilities across multiple severity levels. By configuring Trivy with an exit-code flag, the tool returns a non-zero exit status when HIGH or CRITICAL vulnerabilities are detected, effectively halting the pipeline before deployment. This behavior transforms Trivy from a passive reporting tool into an active security gate within GitHub Actions workflows. Integrating such a scan step between the Docker build and push stages aligns with DevSecOps practices and prevents insecure images from reaching target environments.