diff --git a/lib/Runtime/Types/ActivationObject.cpp b/lib/Runtime/Types/ActivationObject.cpp
index 95888cf1178..557880ed825 100644
--- a/lib/Runtime/Types/ActivationObject.cpp
+++ b/lib/Runtime/Types/ActivationObject.cpp
@@ -10,11 +10,16 @@ namespace Js
 {
     template <> bool VarIsImpl<ActivationObject>(RecyclableObject* instance)
     {
-        return VirtualTableInfo<Js::ActivationObject>::HasVirtualTable(instance) ||
-            VirtualTableInfo<Js::ActivationObjectEx>::HasVirtualTable(instance) ||
-            VirtualTableInfo<Js::PseudoActivationObject>::HasVirtualTable(instance) ||
-            VirtualTableInfo<Js::BlockActivationObject>::HasVirtualTable(instance) ||
-            VirtualTableInfo<Js::ConsoleScopeActivationObject>::HasVirtualTable(instance);
+        return VirtualTableInfo<ActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<ActivationObject>>::HasVirtualTable(instance) ||
+            VirtualTableInfo<ActivationObjectEx>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<ActivationObjectEx>>::HasVirtualTable(instance) ||
+            VirtualTableInfo<PseudoActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<PseudoActivationObject>>::HasVirtualTable(instance) ||
+            VirtualTableInfo<BlockActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<BlockActivationObject>>::HasVirtualTable(instance) ||
+            VirtualTableInfo<ConsoleScopeActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<ConsoleScopeActivationObject>>::HasVirtualTable(instance);
     }
 
     BOOL ActivationObject::HasOwnPropertyCheckNoRedecl(PropertyId propertyId)
@@ -172,7 +177,8 @@ namespace Js
 
     template <> bool VarIsImpl<BlockActivationObject>(RecyclableObject* instance)
     {
-        return VirtualTableInfo<Js::BlockActivationObject>::HasVirtualTable(instance);
+        return VirtualTableInfo<Js::BlockActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<BlockActivationObject>>::HasVirtualTable(instance);
     }
 
     BOOL PseudoActivationObject::InitPropertyScoped(PropertyId propertyId, Var value)
@@ -211,7 +217,8 @@ namespace Js
 
     template <> bool VarIsImpl<PseudoActivationObject>(RecyclableObject* instance)
     {
-        return VirtualTableInfo<Js::PseudoActivationObject>::HasVirtualTable(instance);
+        return VirtualTableInfo<Js::PseudoActivationObject>::HasVirtualTable(instance) ||
+            VirtualTableInfo<CrossSiteObject<PseudoActivationObject>>::HasVirtualTable(instance);
     }
 
 #if ENABLE_TTD
diff --git a/test/Bugs/misc_bugs.js b/test/Bugs/misc_bugs.js
index 68b6abd9520..7b405fe1e28 100644
--- a/test/Bugs/misc_bugs.js
+++ b/test/Bugs/misc_bugs.js
@@ -155,6 +155,16 @@ var tests = [
         var obj2 = {__proto__ : p}; // This should not call the getPrototypeOf
     }
   },
+  {
+    name: "Cross-site activation object",
+    body: function () {
+        var tests = [0, 0];  
+        tests.forEach(function() {
+            var eval = WScript.LoadScript(0, "samethread").eval;
+            eval(0);
+        });
+    }
+  },
   {
     name: "Destructuring declaration should return undefined",
     body: function () {