diff --git a/pom.xml b/pom.xml
index 7dacbd27d..3afbe3b94 100644
--- a/pom.xml
+++ b/pom.xml
@@ -39,7 +39,7 @@
     -->
     <guava.jre.version>30.1-jre</guava.jre.version>
     <gwt.version>2.9.0</gwt.version>
-    <protobuf.version>3.15.5</protobuf.version>
+    <protobuf.version>3.15.6</protobuf.version>
     <!-- Property for protobuf-lite protocArtifact, which isn't a "normal" Maven dep. -->
     <!-- TODO(cpovirk): Use protobuf.version instead. But that requires finding the new way to request the Lite runtime. -->
     <protobuf-lite.protoc.version>3.1.0</protobuf-lite.protoc.version>