diff --git a/requirements.txt b/requirements.txt
index 1e95c031..43bb8cef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -37,3 +37,4 @@ pytz==2017.2
 gunicorn==19.8.1
 humanize==0.5.1
 docutils==0.15.2
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability