diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index f93227c..885224d 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -66,6 +66,15 @@ jobs:
       # Dependency vulnerability scan (binary tool, invoked via official
       # action — Trivy is a Go binary, not an npm package, so it cannot
       # live in package.json scripts as cleanly as audit/lint do).
+      #
+      # On cache miss (the act_runner cache server is currently
+      # unreachable from job containers — see infra/README.md "Cache
+      # server (deferred)"), the action falls back to `git clone
+      # https://github.com/aquasecurity/trivy` to fetch its install
+      # script. Without auth that hits github.com's 60 req/h anonymous
+      # rate limit and `git fetch` fails with "could not read Username".
+      # GITHUBCOM_TOKEN is the same zero-scope github.com PAT we use
+      # for Renovate (per docs/development.md "Dependency updates").
       - uses: aquasecurity/trivy-action@master
         with:
           scan-type: fs
@@ -73,6 +82,8 @@ jobs:
           skip-dirs: node_modules
           exit-code: '1'
           severity: 'CRITICAL,HIGH'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUBCOM_TOKEN }}
       # Secret scan, same reasoning (gitleaks is a Go binary).
       - uses: gitleaks/gitleaks-action@v2
         env: