diff --git a/python/requirements.txt b/python/requirements.txt
index c50b4ee..616e668 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -5,7 +5,7 @@ numpy==1.17.4
 onnx==1.6.0
 onnxruntime==1.0.0
 Pillow==6.2.1
-protobuf==3.11.1
+protobuf==3.18.3
 pyparsing==2.4.5
 python-dateutil==2.8.1
 six==1.13.0
diff --git a/python/requirements_gpu.txt b/python/requirements_gpu.txt
index 38aa20b..62ae40f 100644
--- a/python/requirements_gpu.txt
+++ b/python/requirements_gpu.txt
@@ -6,7 +6,7 @@ onnx==1.6.0
 onnxruntime==1.0.0
 onnxruntime-gpu==1.0.0
 Pillow==6.2.1
-protobuf==3.11.1
+protobuf==3.18.3
 pyparsing==2.4.5
 python-dateutil==2.8.1
 six==1.13.0