diff --git a/requirements/requirements_dev.txt b/requirements/requirements_dev.txt
index 3618b315..800e755f 100644
--- a/requirements/requirements_dev.txt
+++ b/requirements/requirements_dev.txt
@@ -41,3 +41,4 @@ tox>=3.25.0
 twine>=4.0.1
 types-six>=1.1.1
 wheel>=0.37.1
+filelock>=3.20.1 # not directly required, pinned by Snyk to avoid a vulnerability