diff --git a/java/com/google/gerrit/sshd/SshDaemon.java b/java/com/google/gerrit/sshd/SshDaemon.java
index ef356f1687..433e0e92dd 100644
--- a/java/com/google/gerrit/sshd/SshDaemon.java
+++ b/java/com/google/gerrit/sshd/SshDaemon.java
@@ -89,6 +89,7 @@ import org.apache.sshd.common.random.Random;
 import org.apache.sshd.common.random.SingletonRandomFactory;
 import org.apache.sshd.common.session.ConnectionService;
 import org.apache.sshd.common.session.Session;
+import org.apache.sshd.common.session.helpers.DefaultUnknownChannelReferenceHandler;
 import org.apache.sshd.common.util.buffer.Buffer;
 import org.apache.sshd.common.util.buffer.ByteArrayBuffer;
 import org.apache.sshd.common.util.net.SshdSocketAddress;
@@ -226,6 +227,7 @@ public class SshDaemon extends SshServer implements SshInfo, LifecycleListener {
     initMacs(cfg);
     initSignatures();
     initChannels();
+    initUnknownChannelReferenceHandler();
     initForwarding();
     initFileSystemFactory();
     initSubsystems();
@@ -653,6 +655,10 @@ public class SshDaemon extends SshServer implements SshInfo, LifecycleListener {
     setChannelFactories(ServerBuilder.DEFAULT_CHANNEL_FACTORIES);
   }
 
+  private void initUnknownChannelReferenceHandler() {
+    setUnknownChannelReferenceHandler(DefaultUnknownChannelReferenceHandler.INSTANCE);
+  }
+
   private void initSubsystems() {
     setSubsystemFactories(Collections.<NamedFactory<Command>>emptyList());
   }