diff --git a/cJSON.c b/cJSON.c
index 63fb043470706a202287b12c26e95147084dda30..291f2ea7f6d55dd9a36ddfb724c51509a298c904 100644
--- a/cJSON.c
+++ b/cJSON.c
@@ -567,10 +567,16 @@ CJSON_PUBLIC(char*) cJSON_SetValuestring(cJSON *object, const char *valuestring)
         return NULL;
     }
     /* return NULL if the object is corrupted */
-    if (object->valuestring == NULL || valuestring == NULL)
+    if (object->valuestring == NULL)
     {
         return NULL;
     }
+    if (valuestring == NULL)
+    {
+        cJSON_free(object->valuestring);
+        object->valuestring = NULL;
+        return NULL;
+    }
     if (strlen(valuestring) <= strlen(object->valuestring))
     {
         strcpy(object->valuestring, valuestring);