diff --git a/build.gradle b/build.gradle
index 3bfe04754..10ac21ac5 100644
--- a/build.gradle
+++ b/build.gradle
@@ -90,7 +90,7 @@ For more details, please see https://issues.apache.org/jira/browse/AURORA-1169
   ext.junitRev = '4.13.2'
   ext.logbackRev = '1.2.3'
   ext.nettyRev = '4.0.52.Final'
-  ext.protobufRev = '3.15.3'
+  ext.protobufRev = '3.15.6'
   ext.resteasyRev = '3.1.4.Final'
   ext.servletRev = '3.1.0'
   ext.slf4jRev = '1.7.30'