diff --git a/.github/workflows/acceptance_tests_cpython.yml b/.github/workflows/acceptance_tests_cpython.yml
index f15450084a0..2cb859607a6 100644
--- a/.github/workflows/acceptance_tests_cpython.yml
+++ b/.github/workflows/acceptance_tests_cpython.yml
@@ -38,7 +38,7 @@ jobs:
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup python for starting the tests
         uses: actions/setup-python@v2
diff --git a/.github/workflows/acceptance_tests_cpython_pr.yml b/.github/workflows/acceptance_tests_cpython_pr.yml
index f24952d581c..1c4a009cab1 100644
--- a/.github/workflows/acceptance_tests_cpython_pr.yml
+++ b/.github/workflows/acceptance_tests_cpython_pr.yml
@@ -35,7 +35,7 @@ jobs:
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup python for starting the tests
         uses: actions/setup-python@v2
diff --git a/.github/workflows/acceptance_tests_jython.yml b/.github/workflows/acceptance_tests_jython.yml
index 18386143d6d..26f34332d5e 100644
--- a/.github/workflows/acceptance_tests_jython.yml
+++ b/.github/workflows/acceptance_tests_jython.yml
@@ -32,7 +32,7 @@ jobs:
 
     name: Jython (Java ${{ matrix.java }}) ${{ matrix.jython-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup Python 3.6
         uses: actions/setup-python@v2
diff --git a/.github/workflows/unit_tests.yml b/.github/workflows/unit_tests.yml
index a5f5fc168e5..42400be58e4 100644
--- a/.github/workflows/unit_tests.yml
+++ b/.github/workflows/unit_tests.yml
@@ -30,7 +30,7 @@ jobs:
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup python ${{ matrix.python-version }}
         uses: actions/setup-python@v2
@@ -75,7 +75,7 @@ jobs:
 
     name: Jython (Java ${{ matrix.java }}) ${{ matrix.jython-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup Java ${{ matrix.java }}
         uses: actions/setup-java@v1
@@ -116,7 +116,7 @@ jobs:
 
     name: IronPython ${{ matrix.ironpython-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup IronPython ${{ matrix.ironpython-version }}
         run: |
diff --git a/.github/workflows/unit_tests_pr.yml b/.github/workflows/unit_tests_pr.yml
index 418480ea445..c3cda1b0a2f 100644
--- a/.github/workflows/unit_tests_pr.yml
+++ b/.github/workflows/unit_tests_pr.yml
@@ -26,7 +26,7 @@ jobs:
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
 
       - name: Setup python ${{ matrix.python-version }}
         uses: actions/setup-python@v2