diff --git a/src/Angular.js b/src/Angular.js
index 52e74cbf396c..fa1039ef6d51 100644
--- a/src/Angular.js
+++ b/src/Angular.js
@@ -263,7 +263,7 @@ function forEach(obj, iterator, context) {
         obj.forEach(iterator, context, obj);
     } else {
       for (key in obj) {
-        if (obj.hasOwnProperty(key)) {
+        if (hasOwnProperty.call(obj, key)) {
           iterator.call(context, obj[key], key, obj);
         }
       }
diff --git a/src/ng/directive/form.js b/src/ng/directive/form.js
index 29c546d064ff..c62717f3e462 100644
--- a/src/ng/directive/form.js
+++ b/src/ng/directive/form.js
@@ -67,8 +67,8 @@ function FormController(element, attrs, $scope, $animate, $interpolate) {
   var parentForm = form.$$parentForm = element.parent().controller('form') || nullFormCtrl;
 
   // init state
-  form.$error = {};
-  form.$$success = {};
+  form.$error = createMap();
+  form.$$success = createMap();
   form.$pending = undefined;
   form.$name = $interpolate(attrs.name || attrs.ngForm || '')($scope);
   form.$dirty = false;
diff --git a/src/ng/directive/ngModel.js b/src/ng/directive/ngModel.js
index de1a5c491efa..2c25895569cc 100644
--- a/src/ng/directive/ngModel.js
+++ b/src/ng/directive/ngModel.js
@@ -233,8 +233,8 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
   this.$dirty = false;
   this.$valid = true;
   this.$invalid = false;
-  this.$error = {}; // keep invalid keys here
-  this.$$success = {}; // keep valid keys here
+  this.$error = createMap(); // keep invalid keys here
+  this.$$success = createMap(); // keep valid keys here
   this.$pending = undefined; // keep pending keys here
   this.$name = $interpolate($attr.name || '', false)($scope);
 
diff --git a/test/ng/directive/ngModelSpec.js b/test/ng/directive/ngModelSpec.js
index 583414deaa9c..d23cb0298afc 100644
--- a/test/ng/directive/ngModelSpec.js
+++ b/test/ng/directive/ngModelSpec.js
@@ -54,6 +54,22 @@ describe('ngModel', function() {
     });
 
 
+    it('should ignore items in prototype chain when determining validity', inject(function($compile) {
+      dealoc(element);
+      Object.prototype.someProp = true;
+      element = $compile('<form name="form"><input type="text" ng-model="value" name="value"></form>')(scope);
+      var input = element.children().eq(0);
+      ctrl = input.controller('ngModel');
+      var form = element.controller('form');
+      scope.$digest();
+      expect(ctrl.$valid).toBe(true);
+      expect(element.children()).toBeValid();
+      expect(form.$valid).toBe(true);
+      expect(element).toBeValid();
+      delete Object.prototype.someProp;
+    }));
+
+
     describe('setValidity', function() {
 
       function expectOneError() {