diff --git a/.github/workflows/reviewdog.yml b/.github/workflows/reviewdog.yml
index ab2f11d..256e84d 100644
--- a/.github/workflows/reviewdog.yml
+++ b/.github/workflows/reviewdog.yml
@@ -34,7 +34,7 @@ jobs:
   full-review:
     runs-on: ubuntu-latest
     container:
-      image: golang:1.20
+      image: golang:1.20@sha256:bc5f0b5e43282627279fe5262ae275fecb3d2eae3b33977a7fd200c7a760d6f1
     steps:
     - name: clone
       uses: actions/checkout@v3
diff --git a/Dockerfile b/Dockerfile
index 57dd633..8a0a9aa 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
-FROM docker.io/grafana/k6:latest as k6-image
+FROM docker.io/grafana/k6:latest@sha256:10683d5b3803e61567476136b6dcf4ac06df67bdc4a1c9fbbeab61bc916ccd77 as k6-image
 
-FROM alpine as certs
+FROM alpine@sha256:7144f7bab3d4c2648d7e59409f15ec52a18006a128c733fcff20d3a4a54ba44a as certs
 
 RUN apk add --update --no-cache ca-certificates