diff --git a/src/serialization/json_object.cpp b/src/serialization/json_object.cpp
index 8580f93b8..a5eed0cee 100644
--- a/src/serialization/json_object.cpp
+++ b/src/serialization/json_object.cpp
@@ -1173,6 +1173,11 @@ void fromJsonValue(const rapidjson::Value& val, rct::rctSig& sig)
   const auto prunable = val.FindMember("prunable");
   if (prunable != val.MemberEnd())
   {
+    if (!prunable->value.IsObject())
+    {
+      throw WRONG_TYPE("json object");
+    }
+
     rct::keyV pseudo_outs = std::move(sig.get_pseudo_outs());
 
     GET_FROM_JSON_OBJECT(prunable->value, sig.p.rangeSigs, range_proofs);