diff --git a/requirements_dev.txt b/requirements_dev.txt
index fb46f28..e155d86 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -15,3 +15,4 @@ pytest-cov==2.10.1
 
 # deploy
 twine==1.14.0
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability