diff --git a/requirements.txt b/requirements.txt
index bb8f7823b..433e5d309 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,3 +7,4 @@ git+https://github.com/cocodataset/panopticapi.git#egg=panopticapi
 scipy
 onnx
 onnxruntime
+protobuf>=3.20.2 # not directly required, pinned by Snyk to avoid a vulnerability