Supported signature verification for the official Node Docker image?

[BenjaminBruceHammer]

Hello,

We’re trying to verify publisher signatures for the official image docker.io/library/node:24.21.0-alpine3.24.

On 2026-10-12, the tag resolved to this index digest:

sha256:ebfe2f90462722a7a4de65e91990e97fe0d401c70e0e762c5b53302f905ec1c1

For the index and its amd64/arm64 platform and attestation manifests, we checked:

OCI referrers: the API returned empty lists.

Legacy cosign sha256-.sig tags: 404.

OCI referrers fallback sha256- tags: 404.

The index includes attestation manifests with plain in-toto SPDX and SLSA provenance entries. We have not verified those claims.

We are not claiming the image is unsigned; we may be using the wrong discovery methods.

Is there a supported publisher-signature verification procedure for this image? If so, could you point us to:

Where signatures are published.

The verification tooling and procedure.

The trusted key or trust root and, where applicable, expected signer identity and OIDC issuer.

If no supported procedure is currently available, confirmation would also help us make an informed sourcing decision.

We have contacted Docker support and are awaiting a response. If this question belongs with the Docker Official Images publishing team, please point us to the appropriate channel.

Thank you.

[sueun-dev]

I couldn't find a current publisher-signature procedure for Docker Official Images in Docker's public docs. Official Images used to be signed with Docker Content Trust (Notary v1), and in July 2025 Docker started retiring DCT beginning with Official Images, saying a different signing solution for them would follow: https://www.docker.com/blog/retiring-docker-content-trust/

The June 2026 follow-up schedules the full notary.docker.io shutdown for Dec 8, 2026, and doesn't describe a replacement signature for Official Images. For base images with built-in signatures, provenance and SBOMs, it points to Docker Hardened Images instead: https://www.docker.com/blog/docker-content-trust-retirement-and-migration-guidance/

Signing doesn't appear to be in this repo's hands. Back in 2019, under DCT, a docker-library maintainer explained that signing of library/ images was done by Docker Inc, not by the image or Official Images maintainers: docker-library/official-images#1516 (comment). So your Docker support case is the most likely place for a roadmap answer. The June 2026 post also directs shutdown and migration questions to Docker support.

Your empty referrers and 404s look consistent with this, though I can't rule out a signature published somewhere these pages don't mention.

[mustaphaelou]

You're not doing discovery wrong — Docker Official Images (DOI) are not currently signed with cosign/Sigstore or Notation, and DCT is being retired:

• Docker Content Trust (Notary v1) was the historical signing mechanism for DOI, but Docker is retiring it (certificates started expiring Aug 2025; notary.docker.io shuts down Dec 8, 2026). docker trust inspect is no longer reliable for DOI.
• There is no cosign signature or OCI referrer for DOI today; the roadmap request to sign official images with Sigstore is still open (Sign official images with sigstore/cosign docker/roadmap#562).
• What you can verify today: the digest itself (immutable content), plus the in-toto/SLSA provenance attestation manifests attached to the index. Use docker buildx imagetools inspect --raw docker.io/library/node:24.21.0-alpine3.24 (or --format '{{json .Provenance}}') to inspect them; you can validate the SLSA provenance against the build workflow, but that doesn't establish publisher identity by itself.
• If you need cryptographically signed base images, Docker Hardened Images (DHI) ship with signatures, provenance, and SBOMs, or build from a source you sign yourself (cosign/Notation).

So: digest-pin + verify attestations is the realistic path for DOI today; publisher-signature verification isn't available yet.

If this answers it, please mark this comment as the answer — thanks!