diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 53b8535..fab98bc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
     - name: Apt install
       run: cat Aptfile | sudo xargs apt-get install
@@ -42,7 +42,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
     - name: Apt install
       run: cat Aptfile | sudo xargs apt-get install