diff --git a/modules/openapi-generator/src/main/resources/python-flask/requirements.mustache b/modules/openapi-generator/src/main/resources/python-flask/requirements.mustache
index 6e2cf517819..2d1a20a0190 100644
--- a/modules/openapi-generator/src/main/resources/python-flask/requirements.mustache
+++ b/modules/openapi-generator/src/main/resources/python-flask/requirements.mustache
@@ -22,3 +22,4 @@ typing >= 3.5.2.2
 pyyaml < 5.3; python_version<="2.7"
 {{/supportPython2}}
 setuptools >= 21.0.0
+Flask == 1.1.2
diff --git a/samples/server/petstore/python-flask/requirements.txt b/samples/server/petstore/python-flask/requirements.txt
index 72ed547c442..70e1f0c5540 100644
--- a/samples/server/petstore/python-flask/requirements.txt
+++ b/samples/server/petstore/python-flask/requirements.txt
@@ -8,3 +8,4 @@ werkzeug == 0.16.1; python_version=="3.5" or python_version=="3.4"
 swagger-ui-bundle >= 0.0.2
 python_dateutil >= 2.6.0
 setuptools >= 21.0.0
+Flask == 1.1.2