diff --git a/lib/pleroma/web/activity_pub/object_validators/attachment_validator.ex b/lib/pleroma/web/activity_pub/object_validators/attachment_validator.ex
index c8b148280..df102a134 100644
--- a/lib/pleroma/web/activity_pub/object_validators/attachment_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/attachment_validator.ex
@@ -5,6 +5,7 @@
 defmodule Pleroma.Web.ActivityPub.ObjectValidators.AttachmentValidator do
   use Ecto.Schema
 
+  alias Pleroma.EctoType.ActivityPub.ObjectValidators
   alias Pleroma.Web.ActivityPub.ObjectValidators.UrlObjectValidator
 
   import Ecto.Changeset
@@ -15,7 +16,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.AttachmentValidator do
     field(:mediaType, :string, default: "application/octet-stream")
     field(:name, :string)
 
-    embeds_many(:url, UrlObjectValidator)
+    embeds_many :url, UrlObjectValidator, primary_key: false do
+      field(:type, :string)
+      field(:href, ObjectValidators.Uri)
+      field(:mediaType, :string, default: "application/octet-stream")
+    end
   end
 
   def cast_and_validate(data) do
@@ -37,7 +42,18 @@ def changeset(struct, data) do
 
     struct
     |> cast(data, [:type, :mediaType, :name])
-    |> cast_embed(:url, required: true)
+    |> cast_embed(:url, with: &url_changeset/2)
+    |> validate_inclusion(:type, ~w[Link Document Audio Image Video])
+    |> validate_required([:type, :mediaType, :url])
+  end
+
+  def url_changeset(struct, data) do
+    data = fix_media_type(data)
+
+    struct
+    |> cast(data, [:type, :href, :mediaType])
+    |> validate_inclusion(:type, ["Link"])
+    |> validate_required([:type, :href, :mediaType])
   end
 
   def fix_media_type(data) do
@@ -75,6 +91,7 @@ defp fix_url(data) do
 
   def validate_data(cng) do
     cng
+    |> validate_inclusion(:type, ~w[Document Audio Image Video])
     |> validate_required([:mediaType, :url, :type])
   end
 end
diff --git a/lib/pleroma/web/activity_pub/object_validators/url_object_validator.ex b/lib/pleroma/web/activity_pub/object_validators/url_object_validator.ex
deleted file mode 100644
index 881030f38..000000000
--- a/lib/pleroma/web/activity_pub/object_validators/url_object_validator.ex
+++ /dev/null
@@ -1,24 +0,0 @@
-# Pleroma: A lightweight social networking server
-# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
-# SPDX-License-Identifier: AGPL-3.0-only
-
-defmodule Pleroma.Web.ActivityPub.ObjectValidators.UrlObjectValidator do
-  use Ecto.Schema
-
-  alias Pleroma.EctoType.ActivityPub.ObjectValidators
-
-  import Ecto.Changeset
-  @primary_key false
-
-  embedded_schema do
-    field(:type, :string)
-    field(:href, ObjectValidators.Uri)
-    field(:mediaType, :string, default: "application/octet-stream")
-  end
-
-  def changeset(struct, data) do
-    struct
-    |> cast(data, __schema__(:fields))
-    |> validate_required([:type, :href, :mediaType])
-  end
-end