diff --git a/requirements_dev.txt b/requirements_dev.txt
index aea7d00..196dae4 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -4,4 +4,5 @@ twine>=1.13.0
 black>=18.9b0
 pytest>=4.3.0
 pytest-cov>=2.6.1
-coveralls>=1.6.0
\ No newline at end of file
+coveralls>=1.6.0
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability
\ No newline at end of file