diff --git a/.github/workflows/fork_ci_status.yml b/.github/workflows/fork_ci_status.yml
index 56213480b4a0d..14ee14643d9d7 100644
--- a/.github/workflows/fork_ci_status.yml
+++ b/.github/workflows/fork_ci_status.yml
@@ -20,18 +20,20 @@
 # A pull request from a fork to `main` runs `rust.yml` on the fork. This
 # workflow mirrors that run as one `Rust (fork)` check on the pull request, so
 # reviewers see the result without opening the fork. It never checks out or
-# runs code from the pull request: on `pull_request_target` it reads the fork's
-# public run list and creates the check, and on a schedule it updates the
-# active or missing runs of recently updated pull requests plus a rotating
-# slice of all open pull requests. The check is informational. The merge
+# runs code from the pull request: on `workflow_run` of
+# `pull_request_signal.yml` it reads the fork's public run list and creates the
+# check (`pull_request_target` is disabled by ASF infra policy), and on a
+# schedule it updates the active or missing runs of recently updated pull
+# requests plus a rotating slice of all open pull requests. The check is informational. The merge
 # queue runs the full workflow on the merged result and stays the gate.
 #
 # See docs/source/contributor-guide/index.md, "Pull Requests from Forks".
 name: Fork CI status
 
 on:
-  pull_request_target:
-    types: [opened, reopened, synchronize]
+  workflow_run:
+    workflows: ["Pull request signal"]
+    types: [requested]
   schedule:
     - cron: "*/15 * * * *"
   workflow_dispatch:
@@ -47,12 +49,13 @@ permissions:
   pull-requests: read
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || 'update' }}
-  cancel-in-progress: ${{ github.event_name == 'pull_request_target' }}
+  group: ${{ github.workflow }}-${{ github.event.workflow_run.head_repository.full_name && format('{0}-{1}', github.event.workflow_run.head_repository.full_name, github.event.workflow_run.head_branch) || 'update' }}
+  cancel-in-progress: ${{ github.event_name == 'workflow_run' }}
 
 jobs:
   bridge:
     name: Mirror the fork run
+    if: github.event_name != 'workflow_run' || github.event.workflow_run.event == 'pull_request'
     runs-on: ubuntu-slim
     timeout-minutes: 10
     steps:
@@ -211,8 +214,24 @@ jobs:
               core.info(`Created ${CHECK} for ${sha}: ${payload.conclusion || payload.status}`);
             }
 
+            // `workflow_run.pull_requests` is empty for pull requests from
+            // forks, so find the pull request by its head branch and commit.
+            async function pullRequestOf(run) {
+              const { data } = await github.rest.pulls.list({
+                ...upstream,
+                state: 'open',
+                head: `${run.head_repository.owner.login}:${run.head_branch}`,
+              });
+              return data.find((pr) => pr.head.sha === run.head_sha);
+            }
+
             async function notify() {
-              const pr = context.payload.pull_request;
+              // An outdated commit matches nothing, since a newer run mirrors the new head.
+              const pr = await pullRequestOf(context.payload.workflow_run);
+              if (!pr) {
+                core.info('No open pull request for this commit; nothing to mirror.');
+                return;
+              }
               // Only fork PRs to main skip jobs upstream; release branches have
               // no merge queue and keep the full run.
               if (!isForkPrToMain(pr)) {
@@ -312,7 +331,7 @@ jobs:
               }
             }
 
-            if (context.eventName === 'pull_request_target') {
+            if (context.eventName === 'workflow_run') {
               await notify();
             } else {
               await update();
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
index d47bd76c0caa2..06fd5d56ba8ce 100644
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@@ -17,36 +17,57 @@
 
 name: Labeler
 
+# `pull_request_target` is disabled by ASF infra policy. This workflow runs from
+# the default branch when `pull_request_signal.yml` starts, so it never runs the
+# code of a pull request. See that file for details.
 concurrency:
-  group: ${{ github.repository }}-${{ github.head_ref || github.sha }}-${{ github.workflow }}
+  group: ${{ github.repository }}-${{ github.event.workflow_run.head_repository.full_name }}-${{ github.event.workflow_run.head_branch }}-${{ github.workflow }}
   cancel-in-progress: true
 
 on:
-  pull_request_target:
-    types:
-      - opened
-      - edited
-      - synchronize
+  workflow_run:
+    workflows: ["Pull request signal"]
+    types: [requested]
+
+permissions: {}
 
 jobs:
   process:
     name: Process
     runs-on: ubuntu-slim
-    # only run for users whose permissions allow them to update PRs
-    # otherwise labeler is failing:
+    if: github.event.workflow_run.event == 'pull_request'
+    # The token of a `workflow_run` workflow can update PRs from forks.
+    # Previously `pull_request_target` was used for the same reason, see
     # https://github.com/apache/datafusion/issues/3743
     permissions:
       contents: read
       pull-requests: write
     steps:
+      # `workflow_run.pull_requests` is empty for pull requests from forks, so
+      # find the pull request by its head branch and commit. An outdated commit
+      # matches nothing, since a newer run labels the new head.
+      - name: Find the pull request
+        id: pr
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3  # v9.0.0
+        with:
+          script: |
+            const run = context.payload.workflow_run;
+            const { data } = await github.rest.pulls.list({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              state: 'open',
+              head: `${run.head_repository.owner.login}:${run.head_branch}`,
+            });
+            const pr = data.find((pr) => pr.head.sha === run.head_sha);
+            if (pr) core.setOutput('number', String(pr.number));
+            else core.info(`No open pull request for ${run.head_sha}`);
+
       - name: Assign GitHub labels
-        if: |
-          github.event_name == 'pull_request_target' &&
-            (github.event.action == 'opened' ||
-             github.event.action == 'synchronize')
+        if: steps.pr.outputs.number != ''
         uses: actions/labeler@bf12e9b00b37c5c0ca2b87b79b2daf7891dbda13  # v7.0.0
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
+          pr-number: ${{ steps.pr.outputs.number }}
           configuration-path: .github/workflows/labeler/labeler-config.yml
           sync-labels: true
 
diff --git a/.github/workflows/pull_request_signal.yml b/.github/workflows/pull_request_signal.yml
new file mode 100644
index 0000000000000..78be1f0d5a769
--- /dev/null
+++ b/.github/workflows/pull_request_signal.yml
@@ -0,0 +1,42 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# Signal for the workflows that need a write token on a pull request.
+#
+# ASF infra policy disables `pull_request_target`
+# (https://infra.apache.org/github-actions-policy.html), and GitHub is adding a
+# default policy that blocks it. The `workflow_run` workflows below run from the
+# default branch with a write token and never check out or run pull request
+# code. They trigger on the `requested` event of this workflow, which GitHub
+# sends at once for every run, even for a first-time contributor whose run waits
+# for approval:
+#   - labeler.yml
+#   - fork_ci_status.yml
+name: Pull request signal
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+
+permissions: {}
+
+jobs:
+  signal:
+    name: Signal pull request update
+    runs-on: ubuntu-slim
+    steps:
+      - run: echo "This run triggers the workflow_run workflows that handle the pull request."
diff --git a/.github/workflows/release_version_labeler.yaml b/.github/workflows/release_version_labeler.yaml
index 1e44ad842c1d5..6dd3b1f275849 100644
--- a/.github/workflows/release_version_labeler.yaml
+++ b/.github/workflows/release_version_labeler.yaml
@@ -24,16 +24,15 @@ concurrency:
   group: ${{ github.repository }}-${{ github.head_ref || github.sha }}-${{ github.workflow }}
   cancel-in-progress: true
 
+# `pull_request_target` is disabled by ASF infra policy, so label on the push of
+# the merge commit to `main` and look up the merged pull request from it.
 on:
-  pull_request_target:
-    types:
-      - closed
+  push:
     branches:
       - main
 
 jobs:
   label:
-    if: github.event.pull_request.merged == true
     runs-on: ubuntu-slim
     permissions:
       pull-requests: write
diff --git a/ci/scripts/release_version_labeler.js b/ci/scripts/release_version_labeler.js
index 78d17d5671e0a..5c792366378e5 100644
--- a/ci/scripts/release_version_labeler.js
+++ b/ci/scripts/release_version_labeler.js
@@ -40,10 +40,18 @@ module.exports = async ({ github, context }) => {
         }
     }
 
-    await github.rest.issues.addLabels({
+    // A squash merge or a merge queue commit maps to the merged pull request.
+    const { data: pulls } = await github.rest.repos.listPullRequestsAssociatedWithCommit({
         owner: context.repo.owner,
         repo: context.repo.repo,
-        issue_number: context.payload.pull_request.number,
-        labels: [target_version]
+        commit_sha: context.sha
     });
+    for (const pull of pulls.filter((pull) => pull.merged_at && pull.base.ref === 'main')) {
+        await github.rest.issues.addLabels({
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+            issue_number: pull.number,
+            labels: [target_version]
+        });
+    }
 };
diff --git a/ci/scripts/test_fork_ci_status.cjs b/ci/scripts/test_fork_ci_status.cjs
index 46e55c1776941..c7569e8c7f72b 100755
--- a/ci/scripts/test_fork_ci_status.cjs
+++ b/ci/scripts/test_fork_ci_status.cjs
@@ -61,6 +61,11 @@ const pr = {
   },
   base: { ref: "main" },
 };
+const workflowRun = {
+  head_sha: sha,
+  head_branch: "feature",
+  head_repository: { owner: { login: "contributor" } },
+};
 const run = (id, event = "push", conclusion = "success", run_attempt = 1) => ({
   id,
   event,
@@ -92,6 +97,7 @@ async function execute({
   workflowState = "active",
   recentPrs = [pr],
   slice = [pr],
+  openPrs = [pr],
   calls = [],
 }) {
   const writes = [];
@@ -123,7 +129,11 @@ async function execute({
         getWorkflow: async () => ({ data: { state: workflowState } }),
       },
       pulls: {
-        list: async ({ per_page }) => {
+        list: async ({ per_page, head }) => {
+          if (head) {
+            assert.equal(head, "contributor:feature");
+            return { data: openPrs };
+          }
           if (per_page === 1) return { data: [pr], headers: {} };
           assert.equal(per_page, 25);
           return { data: slice };
@@ -141,7 +151,7 @@ async function execute({
     {
       repo: { owner: "apache", repo: "datafusion" },
       eventName: event,
-      payload: { pull_request: pr },
+      payload: { workflow_run: workflowRun },
     },
     { info: () => {} },
     Clock
@@ -161,13 +171,22 @@ function assertRun(write, method, expected) {
 test("notification selects a newer manual run instead of a push run", async () => {
   const latest = run(2, "workflow_dispatch");
   const writes = await execute({
-    event: "pull_request_target",
+    event: "workflow_run",
     runs: [latest, run(1)],
   });
   assert.equal(writes.length, 1);
   assertRun(writes[0], "create", latest);
 });
 
+test("notification skips a commit that is no longer a pull request head", async () => {
+  const writes = await execute({
+    event: "workflow_run",
+    openPrs: [{ ...pr, head: { ...pr.head, sha: "b".repeat(40) } }],
+    runs: [run(1)],
+  });
+  assert.deepEqual(writes, []);
+});
+
 for (const conclusion of ["cancelled", "failure"]) {
   test(`sweep replaces a ${conclusion} push run with a newer manual run`, async () => {
     const previous = run(1, "push", conclusion);