diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index b415d3c7..299d5919 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -15,7 +15,7 @@ jobs:
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
         with:
           fetch-depth: 0
 
@@ -60,7 +60,7 @@ jobs:
     runs-on: ubuntu-latest
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
         with:
           fetch-depth: 0
 
@@ -96,7 +96,7 @@ jobs:
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 5eb08322..aa3c1ebd 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -16,7 +16,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
       with:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.