diff --git a/dev/ci/docker_linux/docker_push.sh b/dev/ci/docker_linux/docker_push.sh
index 84620af6f..152161ec0 100755
--- a/dev/ci/docker_linux/docker_push.sh
+++ b/dev/ci/docker_linux/docker_push.sh
@@ -5,5 +5,8 @@
 
 TAG="${CIRRUS_TAG:-latest}"
 
-sudo docker push "gcr.io/flutter-cirrus/build-flutter-image:$TAG"
+# Convert "+" to "-" to make hotfix tags legal Docker tag names.
+# See https://docs.docker.com/engine/reference/commandline/tag/
+TAG=${TAG/+/-}
 
+sudo docker push "gcr.io/flutter-cirrus/build-flutter-image:$TAG"