diff --git a/src/log4net/Config/XmlConfigurator.cs b/src/log4net/Config/XmlConfigurator.cs
index e6c66956..c9637309 100644
--- a/src/log4net/Config/XmlConfigurator.cs
+++ b/src/log4net/Config/XmlConfigurator.cs
@@ -721,10 +721,10 @@ static private void InternalConfigure(ILoggerRepository repository, Stream confi
                                         // is obsolete: 'Use XmlReaderSettings.DtdProcessing property instead.'
 #if NETSTANDARD1_3 // TODO DtdProcessing.Parse not yet available (https://github.com/dotnet/corefx/issues/4376)
 					settings.DtdProcessing = DtdProcessing.Ignore;
-#elif !NET_4_0 && !MONO_4_0 && !NETSTANDARD2_0
-					settings.ProhibitDtd = false;
+#elif !NET_4_0 && !MONO_4_0
+					settings.ProhibitDtd = true;
 #else
-					settings.DtdProcessing = DtdProcessing.Parse;
+					settings.DtdProcessing = DtdProcessing.Ignore;
 #endif
 
 					// Create a reader over the input stream