diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c5dbbc1..b131ea9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
   test:
     runs-on: dind-small
     container:
-      image: ghcr.io/catthehacker/ubuntu:rust-22.04
+      image: ghcr.io/catthehacker/ubuntu:rust-22.04@sha256:baeacfa8e05a4402c2e17d8a495dadbb7a6062a8ae44eef7c22424d617c53373
 
     steps:
       - uses: actions/checkout@v4