diff --git a/lib/remote/apilistener-sync.cpp b/lib/remote/apilistener-sync.cpp
index 310a35cff..97286f103 100644
--- a/lib/remote/apilistener-sync.cpp
+++ b/lib/remote/apilistener-sync.cpp
@@ -213,6 +213,7 @@ Value ApiListener::ConfigUpdateHandler(const MessageOrigin& origin, const Dictio
 
 	bool configChange = false;
 
+	ObjectLock olock(update);
 	BOOST_FOREACH(const Dictionary::Pair& kv, update) {
 		Zone::Ptr zone = Zone::GetByName(kv.first);