diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7b683a5..0c26caf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,7 @@ jobs:
       matrix:
         ruby-version: ["3.2", "3.3", "3.4"]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
 
       - name: Install devcontainer CLI
         run: npm install -g @devcontainers/cli@0