--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptRuntime.java	Thu Nov 19 14:37:14 2015 +0100
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptRuntime.java	Mon Nov 23 15:26:10 2015 +0100
@@ -756,7 +756,9 @@
 
     /** ECMA 11.9.3 The Abstract Equality Comparison Algorithm */
     private static boolean equals(final Object x, final Object y) {
-        if (x == y) {
+        // We want to keep this method small so we skip reference equality check for numbers
+        // as NaN should return false when compared to itself (JDK-8043608).
+        if (x == y && !(x instanceof Number)) {
             return true;
         }
         if (x instanceof ScriptObject && y instanceof ScriptObject) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8141407.js	Mon Nov 23 15:26:10 2015 +0100
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2015, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ * 
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ * 
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ * 
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * JDK-8141407: Wrong evaluation of a != a when a = NaN
+ *
+ * @test
+ * @run
+ */
+
+function expectNotEqualToSelf(a) {
+    Assert.assertFalse(a == a);
+    Assert.assertFalse(a === a);
+    Assert.assertTrue(a != a);
+    Assert.assertTrue(a !== a);
+}
+
+// In previous versions of Nashorn this failed only on the second assignment,
+// because only then the property slot was widened to object.
+var a = NaN;
+expectNotEqualToSelf(a);
+a = {};
+a = NaN;
+expectNotEqualToSelf(a);
+
+// We do have to do value-based rather than reference-based comparison for
+// java.lang.Double since that class is used to represent primitive numbers
+// in JavaScript.
+var b = new java.lang.Double(NaN);
+expectNotEqualToSelf(b);
+b = {};
+b = new java.lang.Double(NaN);
+expectNotEqualToSelf(b);
+
+// Although float is not used internally by Nashorn, java.lang.Float
+// is handled like a primitive number in most of Nashorn, so for consistency
+// we treat it like java.lang.Double.
+var c = new java.lang.Float(NaN);
+expectNotEqualToSelf(c);
+c = {};
+c = new java.lang.Float(NaN);
+expectNotEqualToSelf(c);