--- a/src/java.base/share/classes/sun/security/ssl/SSLSocketInputRecord.java	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/java.base/share/classes/sun/security/ssl/SSLSocketInputRecord.java	Thu Oct 17 20:53:35 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -302,8 +302,15 @@
                 }
 
                 handshakeFrag.mark();
-                // skip the first byte: handshake type
+
+                // Fail fast for unknown handshake message.
                 byte handshakeType = handshakeFrag.get();
+                if (!SSLHandshake.isKnown(handshakeType)) {
+                    throw new SSLProtocolException(
+                        "Unknown handshake type size, Handshake.msg_type = " +
+                        (handshakeType & 0xFF));
+                }
+
                 int handshakeBodyLen = Record.getInt24(handshakeFrag);
                 handshakeFrag.reset();
                 int handshakeMessageLen =
@@ -313,7 +320,9 @@
                     handshakeBuffer.put(handshakeFrag);
                     handshakeBuffer.rewind();
                     break;
-                } if (remaining == handshakeMessageLen) {
+                }
+
+                if (remaining == handshakeMessageLen) {
                     if (handshakeHash.isHashable(handshakeType)) {
                         handshakeHash.receive(handshakeFrag);
                     }