diff --git a/src/Umbraco.Core/Models/Membership/EntityPermissionCollection.cs b/src/Umbraco.Core/Models/Membership/EntityPermissionCollection.cs
index 5fca079cfc..b8e198bb83 100644
--- a/src/Umbraco.Core/Models/Membership/EntityPermissionCollection.cs
+++ b/src/Umbraco.Core/Models/Membership/EntityPermissionCollection.cs
@@ -17,7 +17,30 @@ namespace Umbraco.Core.Models.Membership
         }
 
         /// <summary>
-        /// Returns the aggregate permissions in the permission set
+        /// Returns the aggregate permissions in the permission set for a single node
+        /// </summary>
+        /// <returns></returns>
+        /// <remarks>
+        /// This value is only calculated once per node
+        /// </remarks>
+        public IEnumerable<string> GetAllPermissions(int entityId)
+        {
+            if (_aggregateNodePermissions == null)
+                _aggregateNodePermissions = new Dictionary<int, string[]>();
+
+            string[] entityPermissions;
+            if (_aggregateNodePermissions.TryGetValue(entityId, out entityPermissions) == false)
+            {
+                entityPermissions = this.Where(x => x.EntityId == entityId).SelectMany(x => x.AssignedPermissions).Distinct().ToArray();
+                _aggregateNodePermissions[entityId] = entityPermissions;
+            }
+            return entityPermissions;
+        }
+
+        private Dictionary<int, string[]> _aggregateNodePermissions;
+
+        /// <summary>
+        /// Returns the aggregate permissions in the permission set for all nodes
         /// </summary>
         /// <returns></returns>
         /// <remarks>
diff --git a/src/Umbraco.Web/WebApi/Filters/FilterAllowedOutgoingContentAttribute.cs b/src/Umbraco.Web/WebApi/Filters/FilterAllowedOutgoingContentAttribute.cs
index 331839780a..808d7c6da1 100644
--- a/src/Umbraco.Web/WebApi/Filters/FilterAllowedOutgoingContentAttribute.cs
+++ b/src/Umbraco.Web/WebApi/Filters/FilterAllowedOutgoingContentAttribute.cs
@@ -101,30 +101,19 @@ namespace Umbraco.Web.WebApi.Filters
                     ids.Add(((dynamic)items[i]).Id);
                 }
                 //get all the permissions for these nodes in one call
-                var permissions = _userService.GetPermissions(user, ids.ToArray()).ToArray();
+                var permissions = _userService.GetPermissions(user, ids.ToArray());
                 var toRemove = new List<dynamic>();
                 foreach (dynamic item in items)
-                {
-                    var nodePermission = permissions.Where(x => x.EntityId == Convert.ToInt32(item.Id)).ToArray();
-                    //if there are no permissions for this id then we need to check what the user's default
-                    // permissions are.
-                    if (nodePermission.Length == 0)
+                {
+                    //get the combined permission set across all user groups for this node
+                    //we're in the world of dynamics here so we need to cast
+                    var nodePermission = ((IEnumerable<string>)permissions.GetAllPermissions(item.Id)).ToArray();
+
+                    //if the permission being checked doesn't exist then remove the item
+                    if (nodePermission.Contains(_permissionToCheck.ToString(CultureInfo.InvariantCulture)) == false)
                     {
-                        //var defaultP = user.DefaultPermissions
-
                         toRemove.Add(item);
-                    }
-                    else
-                    {
-                        foreach (var n in nodePermission)
-                        {
-                            //if the permission being checked doesn't exist then remove the item
-                            if (n.AssignedPermissions.Contains(_permissionToCheck.ToString(CultureInfo.InvariantCulture)) == false)
-                            {
-                                toRemove.Add(item);
-                            }
-                        }
-                    }
+                    }                    
                 }
                 foreach (var item in toRemove)
                 {