diff --git a/.github/workflows/pr-checks.yaml b/.github/workflows/pr-checks.yaml
index 1bb67159..61a5ce3e 100644
--- a/.github/workflows/pr-checks.yaml
+++ b/.github/workflows/pr-checks.yaml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-python@v4
 
       - name: Generate JSON files
@@ -34,7 +34,7 @@ jobs:
   json-lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-python@v4
 
       - name: Lint
@@ -44,7 +44,7 @@ jobs:
   markdown-toc:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-python@v4
       - uses: actions/setup-node@v3
         with: