Security: harden CI against supply chain attacks#3
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- Pin all GitHub Actions to immutable commit SHAs (prevents tag mutation attacks) - Set permissions: read-all at workflow level; grant contents: write only to the host job that creates releases (principle of least privilege) - Isolate CI cache from release cache using branch-prefixed keys to prevent cache poisoning across fork/PR trust boundaries Mitigates the same attack chain used in the TanStack npm compromise (2026-05-11): pull_request_target pwn request + cache poisoning + OIDC token extraction. Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
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Context
On 2026-05-11, TanStack was compromised via a three-stage GitHub Actions supply chain attack:
pull_request_targetPwn Request → cache poisoning across fork↔base trust boundary → OIDC token extraction from runner memory → 84 malicious npm packages published.What this PR does
1. Pin all actions to commit SHAs
Every
uses:reference is now an immutable SHA with the version tag as a comment. A compromised action maintainer account can no longer silently redirect a mutable tag (@v6) to malicious code.2. Least-privilege permissions
permissions: read-allat the workflow level (wascontents: writeglobally in release.yml)contents: writegranted only to thehostjob that actually creates GitHub Releases3. Cache isolation between PRs and release builds (ci.yml)
Cache keys are prefixed with
master-on the main branch andpr-on pull requests, preventing a malicious PR from poisoning the cache that release builds restore from.What we were already safe from
pull_request_targetusage (the root cause of TanStack) — both workflows usepull_requestKeeping SHAs up to date
Enable Dependabot for Actions in
.github/dependabot.ymlto auto-PR SHA updates when new versions are released.🤖 Generated with Claude Code