diff --git a/lib/cpp/src/thrift/protocol/TJSONProtocol.cpp b/lib/cpp/src/thrift/protocol/TJSONProtocol.cpp
index a49a148..80def7f 100644
--- a/lib/cpp/src/thrift/protocol/TJSONProtocol.cpp
+++ b/lib/cpp/src/thrift/protocol/TJSONProtocol.cpp
@@ -899,7 +899,7 @@
       }
       try {
         num = fromString<double>(str);
-      } catch (std::runtime_error e) {
+      } catch (std::runtime_error& e) {
         throw TProtocolException(TProtocolException::INVALID_DATA,
                                      "Expected numeric value; got \"" + str + "\"");
       }
@@ -912,7 +912,7 @@
     result += readJSONNumericChars(str);
     try {
       num = fromString<double>(str);
-    } catch (std::runtime_error e) {
+    } catch (std::runtime_error& e) {
       throw TProtocolException(TProtocolException::INVALID_DATA,
                                    "Expected numeric value; got \"" + str + "\"");
     }