diff --git a/tools/images/kubeadm-aio/Dockerfile b/tools/images/kubeadm-aio/Dockerfile
index 9f9b15d75..2e3c498e4 100644
--- a/tools/images/kubeadm-aio/Dockerfile
+++ b/tools/images/kubeadm-aio/Dockerfile
@@ -75,7 +75,7 @@ RUN set -ex ;\
         jq \
         python-pip \
         gawk ;\
-    pip --no-cache-dir install --upgrade pip ;\
+    pip --no-cache-dir install --upgrade pip==18.1 ;\
     hash -r ;\
     pip --no-cache-dir install --upgrade setuptools ;\
     # NOTE(srwilkers): Pinning ansible to 2.5.5, as pip installs 2.6 by default.
diff --git a/tools/images/mariadb/Dockerfile b/tools/images/mariadb/Dockerfile
index 754259ac3..0ff68ca49 100644
--- a/tools/images/mariadb/Dockerfile
+++ b/tools/images/mariadb/Dockerfile
@@ -6,7 +6,7 @@ RUN set -ex ;\
     apt-get upgrade -y ;\
     apt-get install -y --no-install-recommends \
         python-pip ;\
-    pip --no-cache-dir install --upgrade pip ;\
+    pip --no-cache-dir install --upgrade pip==18.1 ;\
     hash -r ;\
     pip --no-cache-dir install --upgrade setuptools ;\
     pip --no-cache-dir install --upgrade \