[High] Upgrade etcd to 3.5.28 for CVE-2026-33413 and CVE-2026-33343

[AkarshHCL]

Merge Checklist

All boxes should be checked before merging the PR (just tick any boxes which don't apply to this PR)

• The toolchain has been rebuilt successfully (or no changes were made to it)
• The toolchain/worker package manifests are up-to-date
• Any updated packages successfully build (or no packages were changed)
• Packages depending on static components modified in this PR (Golang, *-static subpackages, etc.) have had their Release tag incremented.
• Package tests (%check section) have been verified with RUN_CHECK=y for existing SPEC files, or added to new SPEC files
• All package sources are available
• cgmanifest files are up-to-date and sorted (./cgmanifest.json, ./toolkit/scripts/toolchain/cgmanifest.json, .github/workflows/cgmanifest.json)
• LICENSE-MAP files are up-to-date (./LICENSES-AND-NOTICES/SPECS/data/licenses.json, ./LICENSES-AND-NOTICES/SPECS/LICENSES-MAP.md, ./LICENSES-AND-NOTICES/SPECS/LICENSE-EXCEPTIONS.PHOTON)
• All source files have up-to-date hashes in the *.signatures.json files
• sudo make go-tidy-all and sudo make go-test-coverage pass
• Documentation has been updated to match any changes to the build system
• Ready to merge

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Summary

Upgrade etcd to 3.5.28 to fix GHSA-q8m4-xhhv-38mg and GHSA-rfx7-8w68-q57q

Change Log

• SPECS/etcd/etcd.signatures.json
• SPECS/etcd/etcd.spec
• cgmanifest.json

Does this affect the toolchain?

NO

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-2026-33413
• https://nvd.nist.gov/vuln/detail/CVE-2026-33343

Test Methodology

Screenshot of successful local build-

• Pipeline build id: xxxx

[Kanishk-Bansal]

/azurepipelines run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Kanishk-Bansal]

We can take the upgrade when #16330 this is merged