The problem is actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 probably doesn’t do this same pinning, and the actions ecosystem is such an intertwined mess that any single compromised action can propagate to the rest

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imglorp 2 hours ago | parent | next [-]

Yes, true, but at least the fire won't spread through this one point. Hopefully all of your upstreams can be persuaded to pin also.

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derfniw 2 hours ago | parent | prev [-]

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.

	▲	hobofan 2 hours ago \| parent [-]
		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...