diff --git a/dev-requirements.txt b/dev-requirements.txt
index 133d9a2..dcf56e3 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,3 +1,4 @@
 black==19.3b0
 flake8==3.7.7
 pre-commit==1.14.4
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability