diff --git a/requirements.txt b/requirements.txt
index 64fbddc..1e16ffa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,7 @@ nexmo==2.0.0
 ordereddict==1.1
 pycrypto==2.6.1
 python-jose==1.2.0
-PyYAML==5.1
+PyYAML==5.3.1
 requests==2.20.0
 shellescape==3.4.1
 six==1.10.0