diff --git a/ci/Dockerfile b/ci/Dockerfile
index 6260f680b..9e69427e2 100644
--- a/ci/Dockerfile
+++ b/ci/Dockerfile
@@ -1,6 +1,6 @@
 # initialize from the image
 
-FROM python
+FROM python:3.7.3
 
 ARG TOOLCHAIN_FLAVOR=linux
 ENV TOOLCHAIN_FLAVOR=$TOOLCHAIN_FLAVOR
diff --git a/ci/environment.yml b/ci/environment.yml
index 22fcb1e08..32d348445 100644
--- a/ci/environment.yml
+++ b/ci/environment.yml
@@ -1,6 +1,6 @@
 environment:
   stage: environment
-  image: docker:latest
+  image: docker:18.09.6
   variables:
     GIT_SUBMODULE_STRATEGY: none  # no need to fetch submodules
     CONTAINER_NAME: "$CI_REGISTRY/trezor/trezor-firmware/environment"