diff --git a/requirements.txt b/requirements.txt
index 8f6695e..176d694 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,15 +7,16 @@ Delorean==1.0.0
 Flask==0.12.2
 humanize==0.5.1
 itsdangerous==0.24
-Jinja2==2.10
+Jinja2==2.11.3
 MarkupSafe==1.0
 pymongo==3.6.1
 python-dateutil==2.7.2
 pytz==2018.4
 tzlocal==1.5.1
-Werkzeug==0.14.1
+Werkzeug==0.15.3
 wheel==0.31.0
 zope.interface==4.5.0
 jasmine==3.1.0
 mock==2.0.0
 pyOpenSSL==17.5.0
+pyyaml>=4.2b1 # not directly required, pinned by Snyk to avoid a vulnerability