diff --git a/appengine/standard/firebase/firenotes/backend/requirements.txt b/appengine/standard/firebase/firenotes/backend/requirements.txt
index d4e4be9c865..21d46b5e9eb 100644
--- a/appengine/standard/firebase/firenotes/backend/requirements.txt
+++ b/appengine/standard/firebase/firenotes/backend/requirements.txt
@@ -1,6 +1,6 @@
 Flask==0.11.1
 pyjwt==1.4.2
-flask-cors==3.0.2
+flask-cors==3.0.9
 google-auth==0.3.1
 requests==2.12.1
 requests-toolbelt==0.7.0