diff --git a/requirements.txt b/requirements.txt
index b6f9d0ab298..22f1f45ba22 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,12 +13,12 @@ iso8601>=0.1.11 # MIT
 ipaddress>=1.0.7;python_version<'3.3' # PSF
 keystoneauth1>=2.16.0 # Apache-2.0
 keystonemiddleware>=4.12.0 # Apache-2.0
-lxml>=2.3 # BSD
+lxml!=3.7.0,>=2.3 # BSD
 oauth2client!=4.0.0,>=1.5.0 # Apache-2.0
 oslo.config!=3.18.0,>=3.14.0 # Apache-2.0
 oslo.concurrency>=3.8.0 # Apache-2.0
 oslo.context>=2.9.0 # Apache-2.0
-oslo.db!=4.13.1,!=4.13.2,>=4.11.0 # Apache-2.0
+oslo.db>=4.13.3 # Apache-2.0
 oslo.log>=3.11.0 # Apache-2.0
 oslo.messaging>=5.14.0 # Apache-2.0
 oslo.middleware>=3.0.0 # Apache-2.0
@@ -46,7 +46,7 @@ requests!=2.12.2,>=2.10.0 # Apache-2.0
 retrying!=1.3.0,>=1.2.3 # Apache-2.0
 Routes!=2.0,!=2.1,!=2.3.0,>=1.12.3;python_version=='2.7' # MIT
 Routes!=2.0,!=2.3.0,>=1.12.3;python_version!='2.7' # MIT
-taskflow>=1.26.0 # Apache-2.0
+taskflow>=2.7.0 # Apache-2.0
 rtslib-fb!=2.1.60,!=2.1.61,>=2.1.43 # Apache-2.0
 simplejson>=2.2.0 # MIT
 six>=1.9.0 # MIT