diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2096a8b9..cb6afb8b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ HEAD
 ----
 
 * Fixed warning "unused variable" with GCC 4.4 (issue #912)
+* Fixed warning "maybe uninitialized" (issue #909)
 
 v5.13.4
 -------
diff --git a/src/ArduinoJson/JsonVariantImpl.hpp b/src/ArduinoJson/JsonVariantImpl.hpp
index 98db39ac..f9fe7d7f 100644
--- a/src/ArduinoJson/JsonVariantImpl.hpp
+++ b/src/ArduinoJson/JsonVariantImpl.hpp
@@ -23,6 +23,7 @@ inline JsonVariant::JsonVariant(const JsonArray &array) {
     _content.asArray = const_cast<JsonArray *>(&array);
   } else {
     _type = Internals::JSON_UNDEFINED;
+    _content.asArray = 0;  // <- prevent warning 'maybe-uninitialized'
   }
 }
 
@@ -32,6 +33,7 @@ inline JsonVariant::JsonVariant(const JsonObject &object) {
     _content.asObject = const_cast<JsonObject *>(&object);
   } else {
     _type = Internals::JSON_UNDEFINED;
+    _content.asObject = 0;  // <- prevent warning 'maybe-uninitialized'
   }
 }
 
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 49f5a6a1..b5f7be8a 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -46,6 +46,12 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
 	if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.6)
 		add_compile_options(-Wnoexcept)
 	endif()
+
+	if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.7 AND 
+	   CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
+		# avoid false positive with GCC 4.7
+		add_compile_options(-Wno-maybe-uninitialized)
+	endif()
 endif()
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")