diff --git a/docker/envoy-dev/Dockerfile b/docker/envoy-dev/Dockerfile
index a2c877b..5bfbc81 100644
--- a/docker/envoy-dev/Dockerfile
+++ b/docker/envoy-dev/Dockerfile
@@ -1,4 +1,4 @@
-FROM envoyproxy/envoy:v1.18-latest
+FROM envoyproxy/envoy:v1.18-latest@sha256:0f1c9e46ce1d07faea29e768e703aef50b43564434ed0eb4a195c8d4e8a08327
 
 COPY envoy.yaml /etc/envoy/envoy.yaml
 
diff --git a/docker/envoy/Dockerfile b/docker/envoy/Dockerfile
index a2c877b..5bfbc81 100644
--- a/docker/envoy/Dockerfile
+++ b/docker/envoy/Dockerfile
@@ -1,4 +1,4 @@
-FROM envoyproxy/envoy:v1.18-latest
+FROM envoyproxy/envoy:v1.18-latest@sha256:0f1c9e46ce1d07faea29e768e703aef50b43564434ed0eb4a195c8d4e8a08327
 
 COPY envoy.yaml /etc/envoy/envoy.yaml