diff --git a/tests/Pipfile b/tests/Pipfile
index ac989909ec4..893d55c17fa 100644
--- a/tests/Pipfile
+++ b/tests/Pipfile
@@ -48,6 +48,7 @@ python-jose = "*"
 # depends upon. Pinning Wekrzeug for now until httpbin or its dependencies is
 # updated for the changed API.
 Werkzeug = "==2.0.3"
+flask = "==2.1.3"
 
 [requires]
 python_version = "3"