diff --git a/requirements-test.txt b/requirements-test.txt
index 13af190..5ba0d16 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -8,3 +8,4 @@ pytest-cov >= 2.0.0
 grpcio-tools == 1.62.2
 autopep8
 
+protobuf>=4.25.8 # not directly required, pinned by Snyk to avoid a vulnerability