An actions workflow is an automated job defined in a repository and triggered by events such as pushes, pull requests, releases, or manual dispatches. In practice, it is the engine behind continuous integration and delivery: it can run tests, build artifacts, scan code, publish packages, or deploy services whenever the repository changes.
Workflows matter in security because they often execute with access to repository contents, secrets, and write permissions. Attackers try to abuse that trust by steering event triggers, modifying workflow files, or causing untrusted input from pull requests to reach privileged steps. Defenders reduce risk by limiting workflow permissions, separating trusted and untrusted triggers, protecting branches, reviewing changes to workflow definitions, and making sure secrets are not exposed to jobs that do not need them.