Merge pull request BlogEngine#207 from irbishop/syndication-xxe

Set XmlResolver syndication.axd

Author: rxtur

BlogEngine/BlogEngine.Core/Web/HttpHandlers/SyndicationHandler.cs

@@ -185,7 +185,7 @@ private static List<IPublishable> GenerateItemList(HttpContext context)
                         client.Encoding = Encoding.Default;
                         using (var stream = client.OpenRead(context.Request.QueryString["apml"]))
                         {
-                            var doc = new XmlDocument();
+                            var doc = new XmlDocument() { XmlResolver = null };
                             if (stream != null)
                             {
                                 doc.Load(stream);
@@ -397,4 +397,4 @@ private static void StopServing(HttpContext context)
 
         #endregion
     }
-}
+}