GitHub Actions is GitHub's built-in automation platform. Developers write workflow files, kept in the repository, that run when events happen, such as a push, a pull request or a schedule. Workflows commonly build and test code, publish packages and deploy applications, and they run on machines provided by GitHub or on a company's own runners.
Workflows often need credentials, such as deployment keys and tokens, which are stored as secrets and made available to jobs. That makes the configuration security-sensitive. A workflow that runs code from an untrusted source, such as a pull request from a fork, or that uses a third-party action without checking it, can expose those secrets or let an attacker influence a build.
A risky setting is not proof that anything has been abused. Whether a weakness matters depends on what the workflow can access, who can trigger it and how it is written. Careful configuration can make powerful automation reasonably safe.
To reduce risk, give the workflow token the least permissions it needs, pin third-party actions to a specific commit rather than a moving tag, avoid running untrusted code with access to secrets, and review changes to workflow files like any other sensitive code. Rotate any secrets that may have been exposed.