diff --git a/.github/workflows/back-merge-handler.yml b/.github/workflows/back-merge-handler.yml
index d436ef6..87e0425 100644
--- a/.github/workflows/back-merge-handler.yml
+++ b/.github/workflows/back-merge-handler.yml
@@ -12,7 +12,7 @@ jobs:
     if: github.ref_name == 'master'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           fetch-depth: 0
 
@@ -55,7 +55,7 @@ jobs:
     if: github.ref_name == 'stable'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/update-clients.yml b/.github/workflows/update-clients.yml
index c47a4c6..584c8b7 100644
--- a/.github/workflows/update-clients.yml
+++ b/.github/workflows/update-clients.yml
@@ -32,13 +32,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
           ref: ${{ github.event.inputs.branch }}
 
       - name: Checkout JS Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-js-client'
           token: ${{ secrets.REGULA_GITHUB_PUSH_TOKEN }}
@@ -87,20 +87,20 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Specify Java Version
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961 # v5
         with:
           distribution: 'zulu'
           java-version: 11
           java-package: jdk
 
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
           ref: ${{ github.event.inputs.branch }}
 
       - name: Checkout Java Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-java-client'
           token: ${{ secrets.REGULA_GITHUB_PUSH_TOKEN }}
@@ -148,13 +148,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: "DocumentReader-web-openapi"
           ref: ${{ github.event.inputs.branch }}
 
       - name: Checkout Python Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-python-client'
           token: ${{ secrets.REGULA_GITHUB_PUSH_TOKEN }}
@@ -202,13 +202,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
           ref: ${{ github.event.inputs.branch }}
 
       - name: Checkout C# Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-csharp-client'
           token: ${{ secrets.REGULA_GITHUB_PUSH_TOKEN }}
diff --git a/.github/workflows/validate-spec.yml b/.github/workflows/validate-spec.yml
index 82ba18c..9342bfa 100644
--- a/.github/workflows/validate-spec.yml
+++ b/.github/workflows/validate-spec.yml
@@ -12,10 +12,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
 
       - name: Setup Node
-        uses: actions/setup-node@v6
+        uses: actions/setup-node@249970729cb0ef3589644e2896645e5dc5ba9c38 # v6
         with:
           node-version: 20
           registry-url: https://registry.npmjs.org/
diff --git a/.github/workflows/verify-clients.yml b/.github/workflows/verify-clients.yml
index d9773a3..52f9daa 100644
--- a/.github/workflows/verify-clients.yml
+++ b/.github/workflows/verify-clients.yml
@@ -12,12 +12,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
 
       - name: Checkout Python Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-python-client'
           path: 'python-client'
@@ -34,12 +34,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
 
       - name: Checkout CSharp Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-csharp-client'
           path: 'csharp-client'
@@ -56,12 +56,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
 
       - name: Checkout JS Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-js-client'
           path: 'js-client'
@@ -76,19 +76,19 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Specify Java Version
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961 # v5
         with:
           distribution: 'zulu'
           java-version: 11
           java-package: jdk
 
       - name: Checkout Specification Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           path: 'DocumentReader-web-openapi'
 
       - name: Checkout Java Client Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6
         with:
           repository: 'regulaforensics/DocumentReader-web-java-client'
           path: 'java-client'