diff --git a/docker/build/installers/py27_requirements.txt b/docker/build/installers/py27_requirements.txt
index c73e468aa..c1a084c6b 100644
--- a/docker/build/installers/py27_requirements.txt
+++ b/docker/build/installers/py27_requirements.txt
@@ -4,7 +4,7 @@
 
 # Google infras.
 glog
-protobuf == 3.1
+protobuf == 3.18.3
 python-gflags
 
 # Web utils.