diff --git a/.github/workflows/squad-heartbeat.yml b/.github/workflows/squad-heartbeat.yml
index 2a034b684..c8a62a263 100644
--- a/.github/workflows/squad-heartbeat.yml
+++ b/.github/workflows/squad-heartbeat.yml
@@ -48,7 +48,7 @@ jobs:
 
       - name: Ralph — Apply triage decisions
         if: steps.check-script.outputs.has_script == 'true' && hashFiles('triage-results.json') != ''
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             const fs = require('fs');
@@ -100,7 +100,7 @@ jobs:
       # Copilot auto-assign step (uses PAT if available)
       - name: Ralph — Assign @copilot issues
         if: success()
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           github-token: ${{ secrets.COPILOT_ASSIGN_TOKEN || secrets.GITHUB_TOKEN }}
           script: |
diff --git a/.github/workflows/squad-issue-assign.yml b/.github/workflows/squad-issue-assign.yml
index 74163707a..59e1a2cb6 100644
--- a/.github/workflows/squad-issue-assign.yml
+++ b/.github/workflows/squad-issue-assign.yml
@@ -17,7 +17,7 @@ jobs:
       - uses: actions/checkout@v7.0.1
 
       - name: Identify assigned member and trigger work
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             const fs = require('fs');
@@ -112,7 +112,7 @@ jobs:
       # Separate step: assign @copilot using PAT (required for coding agent)
       - name: Assign @copilot coding agent
         if: github.event.label.name == 'squad:copilot'
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           github-token: ${{ secrets.COPILOT_ASSIGN_TOKEN }}
           script: |
diff --git a/.github/workflows/squad-label-enforce.yml b/.github/workflows/squad-label-enforce.yml
index bac19d50c..91a97c8fa 100644
--- a/.github/workflows/squad-label-enforce.yml
+++ b/.github/workflows/squad-label-enforce.yml
@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v7.0.1
 
       - name: Enforce mutual exclusivity
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             const issue = context.payload.issue;
diff --git a/.github/workflows/squad-triage.yml b/.github/workflows/squad-triage.yml
index af89291f8..2925c2763 100644
--- a/.github/workflows/squad-triage.yml
+++ b/.github/workflows/squad-triage.yml
@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v7.0.1
 
       - name: Triage issue via Lead agent
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             const fs = require('fs');
diff --git a/.github/workflows/sync-squad-labels.yml b/.github/workflows/sync-squad-labels.yml
index 1cf5bab02..2990e0777 100644
--- a/.github/workflows/sync-squad-labels.yml
+++ b/.github/workflows/sync-squad-labels.yml
@@ -17,7 +17,7 @@ jobs:
       - uses: actions/checkout@v7.0.1
 
       - name: Parse roster and sync labels
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             const fs = require('fs');
diff --git a/.github/workflows/trivy.yml b/.github/workflows/trivy.yml
index cb897bfc3..c8f7cbc88 100644
--- a/.github/workflows/trivy.yml
+++ b/.github/workflows/trivy.yml
@@ -177,7 +177,7 @@ jobs:
 
       - name: Create or update security issue
         if: steps.check-vulns.outputs.has_vulns == 'true' && github.event_name == 'schedule'
-        uses: actions/github-script@v9
+        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
             // ISO week date (e.g. 2026-W37); the ISO year can differ from the calendar year near year end.