diff --git a/frontend/dockerfile/cmd/dockerfile-frontend/hack/release b/frontend/dockerfile/cmd/dockerfile-frontend/hack/release
index 053a986df680..da0d91e14834 100755
--- a/frontend/dockerfile/cmd/dockerfile-frontend/hack/release
+++ b/frontend/dockerfile/cmd/dockerfile-frontend/hack/release
@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
 
 . $(dirname $0)/../../../../../hack/util
-set -e
+set -eu
 
-: ${PLATFORMS=}
-: ${DAILY_TARGETS=}
+: "${PLATFORMS=}"
+: "${DAILY_TARGETS=}"
 
 usage() {
   echo "$0 (master|tag|daily) (tag|channel) <repo> [push]"