diff --git a/requirements.txt b/requirements.txt
index 2b1f6eb..038f2b2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ nltk==3.2.5
 numpy==1.14.1
 pbr==3.1.1
 Pillow==5.0.0
-protobuf==3.5.1
+protobuf==3.18.3
 pyparsing==2.2.0
 pyrouge==0.1.3
 python-dateutil==2.6.1