diff --git a/requirements.txt b/requirements.txt
index fc59442..3599c68 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
-flask>=1.0.2 # BSD
+flask>=1.0.2,<2.3.0 # BSD
 github-webhook>=1.0.2 # Apache-2.0
 PyYAML>=3.10.0 # MIT
 PyGithub>=1.43