fix(ci): prevent script injection in GitHub Actions workflows#559
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Bind GitHub context values (github.ref, github.base_ref, step outputs,
and job matrix values) to env vars and reference them as shell/JS
variables instead of interpolating ${{ }} directly into run: and
github-script bodies. Inline expansion lets context data execute as
shell; routing through env: removes the injection surface.
github.base_ref in breaking-change-check.yml is the most notable case —
a fork PR's source branch name flows into 'git fetch'.
Matrix-derived test args (path/ignore/extra-deps) are kept unquoted
where word-splitting into multiple args is intended.
Files: release-prepare.yml, breaking-change-check.yml,
dependabot-auto-merge.yml, integration-testing.yml,
integration-testing-regression.yml
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Claude Security Review: no high-confidence findings. (run) |
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Jun 30, 2026
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Unrelated test failure: |
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Description
Hardens our GitHub Actions workflows against script injection (the AppSec/ACAT "Script Injection in GitHub Actions workflows" finding class).
Several
run:andactions/github-scriptsteps interpolated GitHub context values directly into the script body via${{ … }}. The Actions runner substitutes those before the shell/JS parses the line, so context data can execute as code. The fix follows GitHub's recommended pattern: bind each expression to anenv:variable and reference the shell/JS variable instead (env:assignments are not an injection vector). No behavior changes.Files & what changed
github.base_ref(a fork PR's source branch name) flowed intogit fetch; now viaenv:. Thegithub-scriptstep readssteps.griffe.outputs.exit_codefromprocess.env.steps.metadata.outputs.*(dependency names/versions/update-type) routed throughenv:in both echo steps.matrix.extra-deps,matrix.path,matrix.ignore,matrix.grouprouted throughenv:. The pytest path/deps vars are intentionally left unquoted so they word-split into args exactly as before.github.refin the "must run from main" error message routed throughenv:.Testing
Workflow-only changes. Validated by:
${{ }}expressions remain inside anyrun:/script:body across the entire.github/workflows/tree