fix:(soap-endpoint): skip duplicated xml parameters

src/SoapCore.Tests/InvalidXMLTests.cs

@@ -69,6 +69,63 @@ public async Task MissingNamespace()
 			Assert.IsTrue(context.Response.Body.Length > 0);
 		}
 
+		[TestMethod]
+		public async Task DuplicatedElement()
+		{
+			// Arrange
+			var logger = NullLoggerFactory.Instance.CreateLogger<SoapEndpointMiddleware<CustomMessage>>();
+
+			var serviceCollection = new ServiceCollection();
+			serviceCollection.AddSingleton<DuplicatedElementService>();
+			serviceCollection.AddSoapCore();
+
+			var options = new SoapOptions()
+			{
+				Path = "/Service.asmx",
+				EncoderOptions = new[]
+				{
+					new SoapEncoderOptions
+					{
+						MessageVersion = MessageVersion.Soap11,
+						WriteEncoding = Encoding.UTF8,
+						ReaderQuotas = XmlDictionaryReaderQuotas.Max
+					}
+				},
+				ServiceType = typeof(DuplicatedElementService),
+				SoapModelBounder = new MockModelBounder(),
+				SoapSerializer = SoapSerializer.XmlSerializer
+			};
+
+			var soapCore = new SoapEndpointMiddleware<CustomMessage>(logger, (innerContext) => Task.CompletedTask, options);
+
+			var context = new DefaultHttpContext();
+			context.Request.Path = new PathString("/Service.asmx");
+			context.Request.Method = "POST";
+			context.Response.Body = new MemoryStream();
+
+			// Act
+			var request = @"
+<soapenv:Envelope xmlns:soapenv=""http://schemas.xmlsoap.org/soap/envelope/"" xmlns:rlx=""https://dos.brianfeucht.com/"">
+    <soapenv:Body>
+    <rlx:Test>
+		<eventRef>a</eventRef>
+		<eventRef>b</eventRef>
+		<other>c</other>
+    </rlx:Test>
+  </soapenv:Body>
+</soapenv:Envelope>";
+			context.Request.Body = new MemoryStream(Encoding.UTF8.GetBytes(request), false);
+			context.Request.ContentType = "text/xml; charset=utf-8";
+
+			await soapCore.Invoke(context, serviceCollection.BuildServiceProvider());
+
+			// Assert
+			context.Response.Body.Seek(0, SeekOrigin.Begin);
+			using var response = new StreamReader(context.Response.Body, Encoding.UTF8);
+			var body = await response.ReadToEndAsync();
+			Assert.IsTrue(body.Contains("<TestResult>a c</TestResult>"));
+		}
+
 		[ServiceContract(Namespace = "https://dos.brianfeucht.com/")]
 		public class DenialOfServiceProofOfConcept
 		{
@@ -78,5 +135,15 @@ public Task<string> SpinTheThread(string a, string b)
 				return Task.FromResult("Hello World");
 			}
 		}
+
+		[ServiceContract(Namespace = "https://dos.brianfeucht.com/")]
+		public class DuplicatedElementService
+		{
+			[OperationContract]
+			public Task<string> Test(string eventRef, string other)
+			{
+				return Task.FromResult(eventRef + " " + other);
+			}
+		}
 	}
 }

src/SoapCore/SoapEndpointMiddleware.cs

@@ -676,6 +676,7 @@ private void SetMessageHeadersToProperty(Message requestMessage, object serviceI
 		private object[] GetRequestArguments(Message requestMessage, XmlDictionaryReader xmlReader, OperationDescription operation, HttpContext httpContext)
 		{
 			var arguments = new object[operation.AllParameters.Length];
+			var alreadyProcessedParameters = new bool[operation.AllParameters.Length];
 
 			IEnumerable<Type> serviceKnownTypes = operation
 				.GetServiceKnownTypesHierarchy()
@@ -691,7 +692,7 @@ private object[] GetRequestArguments(Message requestMessage, XmlDictionaryReader
 					while (!xmlReader.EOF)
 					{
 						var parameterInfo = operation.InParameters.FirstOrDefault(p => p.Name == xmlReader.LocalName);
-						if (parameterInfo == null)
+						if (parameterInfo == null || alreadyProcessedParameters[parameterInfo.Index])
 						{
 							xmlReader.Skip();
 							continue;
@@ -704,6 +705,7 @@ private object[] GetRequestArguments(Message requestMessage, XmlDictionaryReader
 						}
 
 						lastParameterIndex = parameterInfo.Index;
+						alreadyProcessedParameters[lastParameterIndex] = true;
 
 						var argumentValue = _serializerHelper.DeserializeInputParameter(
 							xmlReader,