diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/TransportHandlingSockJsService.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/TransportHandlingSockJsService.java
index 9c27ea4e33b0..c3a639a7b3ad 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/TransportHandlingSockJsService.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/TransportHandlingSockJsService.java
@@ -16,17 +16,6 @@
 
 package org.springframework.web.socket.sockjs.transport;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ScheduledFuture;
-
 import org.springframework.context.Lifecycle;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
@@ -46,6 +35,17 @@
 import org.springframework.web.socket.sockjs.frame.SockJsMessageCodec;
 import org.springframework.web.socket.sockjs.support.AbstractSockJsService;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledFuture;
+
 /**
  * A basic implementation of {@link org.springframework.web.socket.sockjs.SockJsService}
  * with support for SPI-based transport handling and session management.
@@ -322,7 +322,8 @@ else if (transportType.supportsCors()) {
 
 	@Override
 	protected boolean validateRequest(String serverId, String sessionId, String transport) {
-		if (!getAllowedOrigins().contains("*") && !TransportType.fromValue(transport).supportsOrigin()) {
+		TransportType transportType = TransportType.fromValue(transport);
+		if (!getAllowedOrigins().contains("*") && (transportType == null || !transportType.supportsOrigin())) {
 			if (logger.isWarnEnabled()) {
 				logger.warn("Origin check has been enabled, but transport " + transport + " does not support it");
 			}
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/handler/DefaultSockJsServiceTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/handler/DefaultSockJsServiceTests.java
index 6b07be824116..239e107a699e 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/handler/DefaultSockJsServiceTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/handler/DefaultSockJsServiceTests.java
@@ -16,19 +16,10 @@
 
 package org.springframework.web.socket.sockjs.transport.handler;
 
-import static org.junit.Assert.*;
-import static org.mockito.BDDMockito.*;
-
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
-
 import org.springframework.http.HttpHeaders;
 import org.springframework.scheduling.TaskScheduler;
 import org.springframework.web.socket.AbstractHttpRequestTests;
@@ -43,6 +34,24 @@
 import org.springframework.web.socket.sockjs.transport.session.StubSockJsServiceConfig;
 import org.springframework.web.socket.sockjs.transport.session.TestSockJsSession;
 
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.mockito.BDDMockito.any;
+import static org.mockito.BDDMockito.eq;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.mock;
+import static org.mockito.BDDMockito.reset;
+import static org.mockito.BDDMockito.verify;
+import static org.mockito.BDDMockito.verifyNoMoreInteractions;
+
 /**
  * Test fixture for {@link org.springframework.web.socket.sockjs.transport.handler.DefaultSockJsService}.
  *
@@ -186,6 +195,18 @@ public void handleTransportRequestXhrSameOrigin() throws Exception {
 		assertEquals(200, this.servletResponse.getStatus());
 	}
 
+	@Test  // SPR-13545
+	public void handleInvalidTransportType() throws Exception {
+		String sockJsPath = sessionUrlPrefix + "invalid";
+		setRequest("POST", sockJsPrefix + sockJsPath);
+		this.service.setAllowedOrigins(Arrays.asList("http://mydomain1.com"));
+		this.servletRequest.addHeader(HttpHeaders.ORIGIN, "http://mydomain2.com");
+		this.servletRequest.setServerName("mydomain2.com");
+		this.service.handleRequest(this.request, this.response, sockJsPath, this.wsHandler);
+
+		assertEquals(404, this.servletResponse.getStatus());
+	}
+
 	@Test
 	public void handleTransportRequestXhrOptions() throws Exception {
 		String sockJsPath = sessionUrlPrefix + "xhr";