--- a/nashorn/src/jdk/nashorn/internal/runtime/ScriptRuntime.java	Tue Oct 22 11:12:36 2013 +0200
+++ b/nashorn/src/jdk/nashorn/internal/runtime/ScriptRuntime.java	Tue Oct 22 11:31:03 2013 +0200
@@ -47,6 +47,7 @@
 import jdk.nashorn.api.scripting.ScriptObjectMirror;
 import jdk.nashorn.internal.codegen.CompilerConstants.Call;
 import jdk.nashorn.internal.ir.debug.JSONWriter;
+import jdk.nashorn.internal.objects.Global;
 import jdk.nashorn.internal.parser.Lexer;
 import jdk.nashorn.internal.runtime.linker.Bootstrap;
 
@@ -258,6 +259,11 @@
             return ((Map<?,?>)obj).keySet().iterator();
         }
 
+        final Object wrapped = Global.instance().wrapAsObject(obj);
+        if (wrapped instanceof ScriptObject) {
+            return ((ScriptObject)wrapped).propertyIterator();
+        }
+
         return Collections.emptyIterator();
     }
 
@@ -336,6 +342,11 @@
             return ((Iterable<?>)obj).iterator();
         }
 
+        final Object wrapped = Global.instance().wrapAsObject(obj);
+        if (wrapped instanceof ScriptObject) {
+            return ((ScriptObject)wrapped).valueIterator();
+        }
+
         return Collections.emptyIterator();
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8026955.js	Tue Oct 22 11:31:03 2013 +0200
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2010, 2013, 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-8026955: for-in should convert primitive values to object
+ *
+ * @test
+ * @run
+ */
+
+Object.prototype[4] = "world";
+String.prototype[3] = "hello";
+Number.prototype[3] = "hello";
+Boolean.prototype[3] = "hello";
+
+function testForIn(x) {
+    for (var i in x) {
+        print(i, x[i]);
+    }
+    for each (var i in x) {
+        print(i);
+    }
+}
+
+testForIn("abc");
+testForIn(false);
+testForIn(3);
+testForIn(null);
+testForIn();
+testForIn(String.prototype);
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8026955.js.EXPECTED	Tue Oct 22 11:31:03 2013 +0200
@@ -0,0 +1,22 @@
+0 a
+1 b
+2 c
+3 hello
+4 world
+a
+b
+c
+hello
+world
+3 hello
+4 world
+hello
+world
+3 hello
+4 world
+hello
+world
+3 hello
+4 world
+hello
+world