1 files changed, 1 insertions, 1 deletions
diff --git a/cpp/src/util/json.cc b/cpp/src/util/json.cc
index 730479c..9d30b66 100644
--- a/cpp/src/util/json.cc
+++ b/cpp/src/util/json.cc
@@ -68,7 +68,7 @@ class Json::JsonImpl {
     assert(value != NULL);
 
     Value::ConstMemberIterator member = value_->FindMember(key.c_str());
-    if (member == NULL || !member->value.IsString()) {
+    if (member == value_->MemberEnd() || !member->value.IsString()) {
       return false;
     }