diff --git a/python-correlation-heatmap/requirements.txt b/python-correlation-heatmap/requirements.txt
index 851afe12..19d96b39 100644
--- a/python-correlation-heatmap/requirements.txt
+++ b/python-correlation-heatmap/requirements.txt
@@ -2,3 +2,4 @@ numpy==1.14.2
 pandas==0.22.0
 mip_helper==0.6.8
 plotly==2.4.1
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability