diff --git a/setup.cfg b/setup.cfg
index 849f9378..1c6a36a9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -47,7 +47,7 @@ install_requires =
     importlib-metadata; python_version<"3.8"
     attrs>=22.2.0
     clize>=5.0.1
-    protobuf>=3.20.3
+    protobuf==3.20.3
     bitstring>=3.1.7
     numpy>=1.24.1
     onnx>=1.13.0