diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index daa9701..ed41e2d 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -40,12 +40,12 @@ jobs:
         uses: actions/checkout@v7.0.1
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.37.7
+        uses: github/codeql-action/init@v4.37.9
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.37.7
+        uses: github/codeql-action/analyze@v4.37.9
         with:
           category: "/language:${{ matrix.language }}"
diff --git a/.github/workflows/comprehensive-quality.yml b/.github/workflows/comprehensive-quality.yml
index 5da7a3c..5c8fcb1 100644
--- a/.github/workflows/comprehensive-quality.yml
+++ b/.github/workflows/comprehensive-quality.yml
@@ -39,7 +39,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7.0.1
       - name: Secret scanning
-        uses: trufflesecurity/trufflehog@v3.97.0
+        uses: trufflesecurity/trufflehog@20652fbbdefffcdaa493a5bf57ab2ac6b1db715b # v3.97.1
         continue-on-error: true
       - name: Dependency vulnerabilities
         run: |
diff --git a/.github/workflows/push-email-notify.yml b/.github/workflows/push-email-notify.yml
index 4f733f4..3c4a47d 100644
--- a/.github/workflows/push-email-notify.yml
+++ b/.github/workflows/push-email-notify.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Send push notification email
-        uses: dawidd6/action-send-mail@v3.12.0
+        uses: dawidd6/action-send-mail@94de994a9f6fffee200243214e17002e2920bb59 # v18
         with:
           server_address: ${{ secrets.SMTP_HOST }}
           server_port: ${{ secrets.SMTP_PORT }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 616ae91..5a1b9b2 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -28,7 +28,7 @@ jobs:
         uses: actions/checkout@v7.0.1
 
       - name: Setup Racket
-        uses: Bogdanp/setup-racket@v1.9.1
+        uses: Bogdanp/setup-racket@2466913449df77df2bad149d1f2fc4e1ea4795dd # v1.15
         with:
           version: ${{ matrix.racket-version }}
           # rackunit ships with the full Racket distribution (already present
@@ -81,7 +81,7 @@ jobs:
         uses: actions/checkout@v7.0.1
 
       - name: Setup Racket
-        uses: Bogdanp/setup-racket@v1.9.1
+        uses: Bogdanp/setup-racket@2466913449df77df2bad149d1f2fc4e1ea4795dd # v1.15
         with:
           version: 'current'