diff --git a/serving/client_requirements.txt b/serving/client_requirements.txt
index 608f2d8..68b7811 100644
--- a/serving/client_requirements.txt
+++ b/serving/client_requirements.txt
@@ -49,7 +49,7 @@ pexpect==4.6.0
 pickleshare==0.7.4
 Pillow==5.1.0
 prompt-toolkit==1.0.15
-protobuf==3.5.2.post1
+protobuf==3.18.3
 ptyprocess==0.5.2
 Pygments==2.2.0
 pyparsing==2.2.0
diff --git a/serving/serving_requirements.txt b/serving/serving_requirements.txt
index 5604e95..33682b4 100644
--- a/serving/serving_requirements.txt
+++ b/serving/serving_requirements.txt
@@ -6,7 +6,7 @@ grpcio==1.12.1
 html5lib==0.9999999
 Markdown==2.6.11
 numpy==1.14.3
-protobuf==3.5.2.post1
+protobuf==3.18.3
 six==1.11.0
 tensorboard==1.8.0
 tensorflow==1.8.0