diff --git a/requirements.txt b/requirements.txt
index a5a33d0..5fe5a60 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,4 @@ psycopg2==2.7.5
 pytz==2018.5
 requests==2.19.1
 urllib3==1.23
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability