diff --git a/requirements.txt b/requirements.txt
index 0c3e849..3fbbc3c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,7 +14,7 @@ google-resumable-media==0.3.1
 googleapis-common-protos==1.5.3
 idna==2.6
 msgpack-python==0.5.6
-protobuf==3.5.2.post1
+protobuf==3.18.3
 pyasn1==0.4.3
 pyasn1-modules==0.2.1
 pymongo==3.6.1