--- a/jdk/src/java.base/share/classes/sun/security/ssl/Handshaker.java	Wed Aug 02 17:15:30 2017 -0700
+++ b/jdk/src/java.base/share/classes/sun/security/ssl/Handshaker.java	Thu Aug 03 00:55:45 2017 +0000
@@ -1034,6 +1034,12 @@
             input.mark(4);
 
             messageType = (byte)input.getInt8();
+            if (HandshakeMessage.isUnsupported(messageType)) {
+                throw new SSLProtocolException(
+                    "Received unsupported or unknown handshake message: " +
+                    messageType);
+            }
+
             messageLen = input.getInt24();
 
             if (input.available() < messageLen) {