diff --git a/lower-constraints.txt b/lower-constraints.txt
index 616bc902..456bb16f 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -15,7 +15,7 @@ iso8601==0.1.11
 Jinja2==2.10
 keystoneauth1==3.4.0
 linecache2==1.0.0
-MarkupSafe==1.0
+MarkupSafe==1.1.1
 mox3==0.20.0
 msgpack-python==0.4.0
 netaddr==0.7.18
@@ -33,7 +33,7 @@ pyparsing==2.1.0
 python-mimeparse==1.6.0
 python-subunit==1.0.0
 pytz==2013.6
-PyYAML==3.12
+PyYAML==5.1
 requests==2.14.2
 requests-mock==1.2.0
 requestsexceptions==1.2.0
diff --git a/requirements.txt b/requirements.txt
index 4a0c5ed9..2204536a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ oslo.config>=5.2.0 # Apache-2.0
 oslo.context>=2.22.0 # Apache-2.0
 oslo.i18n>=3.15.3 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
-PyYAML>=3.12 # MIT
+PyYAML>=5.1 # MIT
 six>=1.10.0 # MIT
 stevedore>=1.20.0 # Apache-2.0
 oslo.utils>=3.40.0 # Apache-2.0