diff --git a/requirements.txt b/requirements.txt
index c5400455..bdaa42fd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 jsonschema>=2.4.0
 aiohttp>=1.3.0,<=1.4.0
-aiohttp_cors>=0.4.0
-yarl>=0.9.8
+aiohttp_cors==0.5.0
+yarl>=0.9.8,<0.10
 typing>=3.5.3.0 # Otherwise yarl fail with python 3.4 
 Jinja2>=2.7.3
 raven>=5.23.0