Prevent script injection in GitHub Actions workflows#939
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ShubhamChaturvedi7 merged 1 commit intoJul 16, 2026
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Bind untrusted GitHub context values to intermediate environment variables instead of interpolating them directly into inline run scripts. User-controlled inputs (workflow_dispatch inputs and pull_request event fields) spliced into shell scripts allow command injection on the runner. - go-release.yml: move github.event.inputs.project-name/version into env vars in the release-dir, run-release, and print-diff steps; quote all shell references - smithy-diff.yml: move github.event.pull_request.user.login, github.actor, and github.repository into env vars in the comment step Addresses AWS AppSec ACAT finding (Script Injection in GitHub Actions workflows). sim: https://t.corp.amazon.com/V2263272257
kessplas
approved these changes
Jul 15, 2026
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Summary
Fixes a script injection in GitHub Actions workflows finding. Untrusted, user-controlled GitHub context values were interpolated directly into inline
run:shell scripts, allowing command injection on the runner. Each such value is now bound to an intermediateenv:variable and referenced as a properly quoted shell variable (data, not script text) — the mitigation recommended by GitHub's hardening guide.Changes
.github/workflows/go-release.yml— movegithub.event.inputs.project-name/versionintoenv:in theGet release directory name,Run Go release automation script, andprint diffsteps; quote all shell references..github/workflows/smithy-diff.yml— movegithub.event.pull_request.user.login,github.actor, andgithub.repositoryintoenv:in the comment step.Testing
github.event.*/github.actorinterpolation remains inside anyrun:block (all remaining references are withinenv:blocks).sim: https://t.corp.amazon.com/V2263272257