diff --git a/Dockerfile.cnm b/Dockerfile.cnm
index 98e978be29..3c9d670139 100644
--- a/Dockerfile.cnm
+++ b/Dockerfile.cnm
@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/oss/mirror/docker.io/library/ubuntu:18.04
+FROM mcr.microsoft.com/oss/mirror/docker.io/library/ubuntu:20.04
 ARG CNM_BUILD_DIR
 
 # Install dependencies.