diff --git a/requirements/ci.txt b/requirements/ci.txt
index 8c7da7e5f87..4424cfd7122 100644
--- a/requirements/ci.txt
+++ b/requirements/ci.txt
@@ -4,3 +4,4 @@ six==1.14.0
 pluggy==0.13.1
 tox==3.19.0
 tox-pip-extensions==1.6.0
+filelock>=3.20.1 # not directly required, pinned by Snyk to avoid a vulnerability