This action runs inside other people's CI with their secrets, so it is treated as supply-chain code.

Please report privately via Security → Report a vulnerability on this repository (GitHub private vulnerability reporting). Do not open a public issue or PR for anything exploitable.

Only the latest release, which the floating v1 tag always points to, gets fixes. Pin to a full commit SHA if you need a frozen version, and let Dependabot move it.

• The Swift toolchain is installed only if its detached signature verifies against a release key vendored in keys/ and pinned by fingerprint. Keys are never fetched from the server that serves the tarball.
• Every third-party action, here and in the workflows, is pinned to a full commit SHA. Dependabot proposes updates after a 7-day cooldown.
• Inputs never get interpolated into shell scripts; they reach scripts as environment variables, and swift-version must look like a release number.
• Workflows run with least-privilege GITHUB_TOKEN permissions, and only the steps that push hold credentials. zizmor audits every PR.

• A toolchain restored from the actions/cache toolchain cache is not re-verified. Cache entries are scoped to the consuming repository, and only workflow runs in that repository can write them.
• SwiftPM resolves your package's dependencies from Package.resolved as written; this action does not audit them.