diff --git a/Dockerfile.linux b/Dockerfile.linux
index 5d3a1533a9..4ac86a62e7 100644
--- a/Dockerfile.linux
+++ b/Dockerfile.linux
@@ -1,4 +1,4 @@
-FROM ubuntu:16.04
+FROM ubuntu:16.04@sha256:1f1a2d56de1d604801a9671f301190704c25d604a416f59e03c04f5c6ffee0d6
 
 ARG THREADS=1
 ARG QT_VERSION=v5.15.14-lts-lgpl