diff --git a/e2e-test-server/constraints.txt b/e2e-test-server/constraints.txt
index 43589a85..0f13f2dc 100644
--- a/e2e-test-server/constraints.txt
+++ b/e2e-test-server/constraints.txt
@@ -7,7 +7,7 @@ click==8.1.7
 cloudevents==1.11.0
 Deprecated==1.2.14
 deprecation==2.1.0
-Flask==3.0.0
+Flask==3.1.3
 functions-framework==3.8.0
 google-api-core==2.12.0
 google-auth==2.23.3