diff --git a/test/pleroma/web/activity_pub/activity_pub_controller_test.exs b/test/pleroma/web/activity_pub/activity_pub_controller_test.exs
index 42cb35669..8cadf6686 100644
--- a/test/pleroma/web/activity_pub/activity_pub_controller_test.exs
+++ b/test/pleroma/web/activity_pub/activity_pub_controller_test.exs
@@ -794,6 +794,92 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
       refute Activity.get_by_ap_id(data["id"])
     end
 
+    test "does not create a forged post signed by a different actor", %{conn: conn} do
+      alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+      bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
+      object_id = "https://example.com/objects/inbox-signed-forged-note"
+
+      data = %{
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "type" => "Create",
+        "actor" => bob.ap_id,
+        "id" => "https://example.com/activities/inbox-signed-forged-create",
+        "context" => "https://example.com/contexts/inbox-signed-forged-create",
+        "to" => ["https://www.w3.org/ns/activitystreams#Public"],
+        "cc" => [],
+        "object" => %{
+          "type" => "Note",
+          "id" => object_id,
+          "actor" => bob.ap_id,
+          "attributedTo" => bob.ap_id,
+          "context" => "https://example.com/contexts/inbox-signed-forged-create",
+          "content" => "forged post",
+          "published" => "2024-07-25T13:33:31Z",
+          "to" => ["https://www.w3.org/ns/activitystreams#Public"],
+          "cc" => []
+        }
+      }
+
+      Mox.expect(Pleroma.StubbedHTTPSignaturesMock, :validate_conn, fn _conn -> true end)
+
+      conn =
+        conn
+        |> put_req_header("content-type", "application/activity+json")
+        |> put_req_header("date", "Thu, 25 Jul 2024 13:33:31 GMT")
+        |> put_req_header("digest", "SHA-256=fake-digest")
+        |> put_req_header(
+          "signature",
+          "keyId=\"#{alice.ap_id}#main-key\",algorithm=\"rsa-sha256\",headers=\"(request-target) host date digest content-type\",signature=\"fake-signature\""
+        )
+        |> post("/inbox", data)
+
+      assert conn.assigns.valid_signature == false
+      assert "ok" == json_response(conn, 200)
+
+      assert [{:cancel, :actor_signature_mismatch}] =
+               ObanHelpers.perform(all_enqueued(worker: ReceiverWorker))
+
+      refute Activity.get_by_ap_id(data["id"])
+      refute Object.get_by_ap_id(object_id)
+    end
+
+    test "does not create a forged like signed by a different actor", %{conn: conn} do
+      alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+      bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
+      note = insert(:note)
+
+      data = %{
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "type" => "Like",
+        "actor" => bob.ap_id,
+        "id" => "https://example.com/activities/inbox-signed-forged-like",
+        "to" => ["https://www.w3.org/ns/activitystreams#Public"],
+        "cc" => [],
+        "object" => note.data["id"]
+      }
+
+      Mox.expect(Pleroma.StubbedHTTPSignaturesMock, :validate_conn, fn _conn -> true end)
+
+      conn =
+        conn
+        |> put_req_header("content-type", "application/activity+json")
+        |> put_req_header("date", "Thu, 25 Jul 2024 13:33:31 GMT")
+        |> put_req_header("digest", "SHA-256=fake-digest")
+        |> put_req_header(
+          "signature",
+          "keyId=\"#{alice.ap_id}#main-key\",algorithm=\"rsa-sha256\",headers=\"(request-target) host date digest content-type\",signature=\"fake-signature\""
+        )
+        |> post("/inbox", data)
+
+      assert conn.assigns.valid_signature == false
+      assert "ok" == json_response(conn, 200)
+
+      assert [{:cancel, :actor_signature_mismatch}] =
+               ObanHelpers.perform(all_enqueued(worker: ReceiverWorker))
+
+      refute Activity.get_by_ap_id(data["id"])
+    end
+
     test "accept follow activity", %{conn: conn} do
       clear_config([:instance, :federating], true)
       relay = Relay.get_actor()
diff --git a/test/pleroma/workers/receiver_worker_test.exs b/test/pleroma/workers/receiver_worker_test.exs
index 9dccd739b..5e18fe771 100644
--- a/test/pleroma/workers/receiver_worker_test.exs
+++ b/test/pleroma/workers/receiver_worker_test.exs
@@ -11,6 +11,7 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
 
   alias Pleroma.User
   alias Pleroma.Web.CommonAPI
+  alias Pleroma.Web.ActivityPub.UserView
   alias Pleroma.Web.Federator
   alias Pleroma.Workers.ReceiverWorker
 
@@ -27,28 +28,34 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
     ]
   end
 
-  defp assert_mismatched_signature_cancelled(params) do
-    with_mocks [
-      {Pleroma.Signature, [:passthrough],
-       [
-         refetch_public_key: fn _conn -> {:ok, :fake_public_key} end,
-         validate_signature: fn _conn -> true end
-       ]},
-      {Pleroma.Web.Federator, [:passthrough],
-       [perform: fn :incoming_ap_doc, _params -> {:ok, :processed} end]}
-    ] do
-      assert {:ok, oban_job} =
-               Federator.incoming_ap_doc(%{
-                 method: "POST",
-                 req_headers: mismatched_signature_headers(),
-                 request_path: "/inbox",
-                 params: params,
-                 query_string: ""
-               })
+  defp expect_signature_from(%User{} = signer) do
+    signer_json = UserView.render("user.json", %{user: signer}) |> Map.delete("featured")
 
-      assert {:cancel, :actor_signature_mismatch} = ReceiverWorker.perform(oban_job)
-      refute called(Pleroma.Web.Federator.perform(:incoming_ap_doc, :_))
-    end
+    Tesla.Mock.mock(fn
+      %{url: url} when url == signer.ap_id ->
+        %Tesla.Env{
+          status: 200,
+          body: Jason.encode!(signer_json),
+          headers: HttpRequestMock.activitypub_object_headers()
+        }
+    end)
+
+    Mox.expect(Pleroma.StubbedHTTPSignaturesMock, :validate_conn, fn _conn -> true end)
+  end
+
+  defp assert_mismatched_signature_cancelled(params, signer) do
+    expect_signature_from(signer)
+
+    assert {:ok, oban_job} =
+             Federator.incoming_ap_doc(%{
+               method: "POST",
+               req_headers: mismatched_signature_headers(),
+               request_path: "/inbox",
+               params: params,
+               query_string: ""
+             })
+
+    assert {:cancel, :actor_signature_mismatch} = ReceiverWorker.perform(oban_job)
   end
 
   test "it does not retry MRF reject" do
@@ -341,7 +348,7 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
   end
 
   test "cancels when signature actor does not match payload actor" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
 
     note = insert(:note, user: bob, object_local: false)
@@ -377,11 +384,9 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       }
     }
 
-    with_mock Pleroma.Signature, [:passthrough],
-      refetch_public_key: fn _conn -> {:ok, :fake_public_key} end,
-      validate_signature: fn _conn -> true end do
-      assert {:cancel, :actor_signature_mismatch} = ReceiverWorker.perform(oban_job)
-    end
+    expect_signature_from(alice)
+
+    assert {:cancel, :actor_signature_mismatch} = ReceiverWorker.perform(oban_job)
   end
 
   test "Federator preserves request metadata needed for ReceiverWorker signature checks" do
@@ -411,7 +416,7 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
   end
 
   test "cancels signature actor mismatch through Federator-created jobs" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
 
     note = insert(:note, user: bob, object_local: false)
@@ -425,11 +430,11 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => note.data
     }
 
-    assert_mismatched_signature_cancelled(update)
+    assert_mismatched_signature_cancelled(update, alice)
   end
 
   test "cancels signature actor mismatch before processing a forged Create" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
 
     create = %{
@@ -450,11 +455,11 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       }
     }
 
-    assert_mismatched_signature_cancelled(create)
+    assert_mismatched_signature_cancelled(create, alice)
   end
 
   test "cancels signature actor mismatch before actually creating a forged post" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
 
     object_id = "https://example.com/objects/actually-forged-note"
@@ -479,6 +484,8 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       }
     }
 
+    expect_signature_from(alice)
+
     assert {:ok, oban_job} =
              Federator.incoming_ap_doc(%{
                method: "POST",
@@ -493,7 +500,7 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
   end
 
   test "cancels signature actor mismatch before processing a forged Like" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
     note = insert(:note)
 
@@ -506,11 +513,11 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => note.data["id"]
     }
 
-    assert_mismatched_signature_cancelled(like)
+    assert_mismatched_signature_cancelled(like, alice)
   end
 
   test "cancels signature actor mismatch before actually creating a forged Like" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
     note = insert(:note)
 
@@ -523,6 +530,8 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => note.data["id"]
     }
 
+    expect_signature_from(alice)
+
     assert {:ok, oban_job} =
              Federator.incoming_ap_doc(%{
                method: "POST",
@@ -537,7 +546,7 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
   end
 
   test "cancels signature actor mismatch before processing a forged Announce" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
     note = insert(:note)
 
@@ -550,11 +559,11 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => note.data["id"]
     }
 
-    assert_mismatched_signature_cancelled(announce)
+    assert_mismatched_signature_cancelled(announce, alice)
   end
 
   test "cancels signature actor mismatch before processing a forged Follow" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
     followed = insert(:user)
 
@@ -567,11 +576,11 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => followed.ap_id
     }
 
-    assert_mismatched_signature_cancelled(follow)
+    assert_mismatched_signature_cancelled(follow, alice)
   end
 
   test "cancels signature actor mismatch before processing a forged Undo" do
-    _alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
+    alice = insert(:user, local: false, ap_id: "https://example.com/users/alice")
     bob = insert(:user, local: false, ap_id: "https://example.com/users/bob")
 
     undo = %{
@@ -583,6 +592,6 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
       "object" => "https://example.com/activities/existing-bob-activity"
     }
 
-    assert_mismatched_signature_cancelled(undo)
+    assert_mismatched_signature_cancelled(undo, alice)
   end
 end