diff --git a/requirements.txt b/requirements.txt
index 4fbb1bdbf..ea471536d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,8 +19,8 @@ oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.service>=1.24.0 # Apache-2.0
 oslo.utils>=3.28.0 # Apache-2.0
 python-barbicanclient!=4.5.0,!=4.5.1,>=4.0.0 # Apache-2.0
-pyasn1!=0.2.3 # BSD
-pyasn1-modules # BSD
+pyasn1!=0.2.3,>=0.1.8 # BSD
+pyasn1-modules>=0.0.6 # BSD
 pyOpenSSL>=16.2.0 # Apache-2.0
 stevedore>=1.20.0 # Apache-2.0
 cryptography!=2.0,>=1.9 # BSD/Apache-2.0