diff --git a/CHANGELOG-nightly.md b/CHANGELOG-nightly.md
index 665d4306c8..d78f0e794c 100644
--- a/CHANGELOG-nightly.md
+++ b/CHANGELOG-nightly.md
@@ -2,6 +2,7 @@
 
 Note: Breaking changes between versions are indicated by "💥".
 
+- [Security] On Kubernetes, convert all NodePort services to ClusterIP to guarantee network isolation from outside the cluster.
 - 💥[Improvement] Drop Python 3.5 compatibility.
 - [Bugfix] Fix docker-compose project name in development on nightly branch.
 - 💥[Bugfix] No longer track the Tutor version number in resource labels (and label selectors, which breaks the update of Deployment resources), but instead do so in resource annotations.
diff --git a/tutor/templates/k8s/services.yml b/tutor/templates/k8s/services.yml
index b768098f8d..2e00b9b062 100644
--- a/tutor/templates/k8s/services.yml
+++ b/tutor/templates/k8s/services.yml
@@ -21,7 +21,7 @@ kind: Service
 metadata:
   name: cms
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 8000
       protocol: TCP
@@ -35,7 +35,7 @@ kind: Service
 metadata:
   name: lms
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 8000
       protocol: TCP
@@ -49,7 +49,7 @@ kind: Service
 metadata:
   name: elasticsearch
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 9200
       protocol: TCP
@@ -63,7 +63,7 @@ kind: Service
 metadata:
   name: mongodb
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 27017
       protocol: TCP
@@ -77,7 +77,7 @@ kind: Service
 metadata:
   name: mysql
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 3306
       protocol: TCP
@@ -91,7 +91,7 @@ kind: Service
 metadata:
   name: redis
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: {{ REDIS_PORT }}
       protocol: TCP
@@ -105,7 +105,7 @@ kind: Service
 metadata:
   name: smtp
 spec:
-  type: NodePort
+  type: ClusterIP
   ports:
     - port: 8025
       protocol: TCP