diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f64bf69..7cc182c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     timeout-minutes: 15
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
     - name: Set up JDK 17
       uses: actions/setup-java@v4
       with: