Well, it is a git commit hash of the action repo that contains the transpiled/bundled javascript.

Like: https://github.com/actions/checkout/tree/11bd71901bbe5b1630c...

So I'm pretty sure that for the same commit hash, I'll be executing the same content.

This is true specifically for actions/checkout, but composite actions can have other actions as dependencies, and unless the composite action pins the versions of its dependencies, it is vulnerable for this attack.

This article[0] gives a good overview of the challenges, and also has a link to a concrete attack where this was exploited.

[0]: https://nesbitt.io/2025/12/06/github-actions-package-manager...