diff --git a/changelog.d/c2s-rate-limit.security b/changelog.d/c2s-rate-limit.security
new file mode 100644
index 000000000..8cab4a309
--- /dev/null
+++ b/changelog.d/c2s-rate-limit.security
@@ -0,0 +1 @@
+Rate limit ActivityPub C2S outbox posts and emoji reactions
diff --git a/lib/pleroma/web/activity_pub/activity_pub_controller.ex b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
index a45f7bf27..ae45bc748 100644
--- a/lib/pleroma/web/activity_pub/activity_pub_controller.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
@@ -26,6 +26,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
   alias Pleroma.Web.Plugs.EnsureAuthenticatedPlug
   alias Pleroma.Web.Plugs.FederatingPlug
   alias Pleroma.Web.Plugs.OAuthScopesPlug
+  alias Pleroma.Web.Plugs.RateLimiter
 
   require Logger
 
@@ -66,6 +67,9 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
     when action in [:followers, :following]
   )
 
+  # Shares the per-user bucket with Mastodon API status actions and emoji reactions.
+  plug(RateLimiter, [name: :statuses_actions] when action == :update_outbox)
+
   plug(Majic.Plug, [pool: Pleroma.MajicPool] when action in [:upload_media])
 
   plug(
diff --git a/lib/pleroma/web/pleroma_api/controllers/emoji_reaction_controller.ex b/lib/pleroma/web/pleroma_api/controllers/emoji_reaction_controller.ex
index 82abfce7f..57e3a2d5b 100644
--- a/lib/pleroma/web/pleroma_api/controllers/emoji_reaction_controller.ex
+++ b/lib/pleroma/web/pleroma_api/controllers/emoji_reaction_controller.ex
@@ -12,6 +12,7 @@ defmodule Pleroma.Web.PleromaAPI.EmojiReactionController do
   alias Pleroma.Web.CommonAPI
   alias Pleroma.Web.MastodonAPI.StatusView
   alias Pleroma.Web.Plugs.OAuthScopesPlug
+  alias Pleroma.Web.Plugs.RateLimiter
 
   plug(Pleroma.Web.ApiSpec.CastAndValidate)
   plug(OAuthScopesPlug, %{scopes: ["write:statuses"]} when action in [:create, :delete])
@@ -22,6 +23,14 @@ defmodule Pleroma.Web.PleromaAPI.EmojiReactionController do
     when action == :index
   )
 
+  plug(
+    RateLimiter,
+    [name: :status_id_action, bucket_name: "status_id_action:emoji_react", params: [:id]]
+    when action in [:create, :delete]
+  )
+
+  plug(RateLimiter, [name: :statuses_actions] when action in [:create, :delete])
+
   defdelegate open_api_operation(action), to: Pleroma.Web.ApiSpec.EmojiReactionOperation
 
   action_fallback(Pleroma.Web.MastodonAPI.FallbackController)
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 e1376b460..f5c0e6a82 100644
--- a/test/pleroma/web/activity_pub/activity_pub_controller_test.exs
+++ b/test/pleroma/web/activity_pub/activity_pub_controller_test.exs
@@ -2709,6 +2709,43 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
 
       assert result == "Character limit (5 characters) exceeded, contains 11 characters"
     end
+
+    test "it is rate limited", %{conn: conn, activity: activity} do
+      clear_config([:rate_limit, :statuses_actions], {60_000, 2})
+      user = insert(:user)
+
+      conn =
+        conn
+        |> assign(:user, user)
+        |> put_req_header("content-type", "application/activity+json")
+
+      for _ <- 1..2 do
+        conn
+        |> post("/users/#{user.nickname}/outbox", activity)
+        |> json_response(201)
+      end
+
+      assert conn
+             |> post("/users/#{user.nickname}/outbox", activity)
+             |> json_response(429) == %{"error" => "Throttled"}
+    end
+
+    test "it shares the rate limit with the Mastodon API", %{activity: activity} do
+      clear_config([:rate_limit, :statuses_actions], {60_000, 2})
+      %{user: user, conn: conn} = oauth_access(["write"])
+
+      for _ <- 1..2 do
+        conn
+        |> put_req_header("content-type", "application/json")
+        |> post("/api/v1/statuses", %{status: "cofe"})
+        |> json_response(200)
+      end
+
+      assert conn
+             |> put_req_header("content-type", "application/activity+json")
+             |> post("/users/#{user.nickname}/outbox", activity)
+             |> json_response(429) == %{"error" => "Throttled"}
+    end
   end
 
   describe "/relay/followers" do
diff --git a/test/pleroma/web/pleroma_api/controllers/emoji_reaction_controller_test.exs b/test/pleroma/web/pleroma_api/controllers/emoji_reaction_controller_test.exs
index 8fcdb233b..12b037a21 100644
--- a/test/pleroma/web/pleroma_api/controllers/emoji_reaction_controller_test.exs
+++ b/test/pleroma/web/pleroma_api/controllers/emoji_reaction_controller_test.exs
@@ -477,4 +477,53 @@ defmodule Pleroma.Web.PleromaAPI.EmojiReactionControllerTest do
            |> get("/api/v1/pleroma/statuses/#{activity_id}/reactions/🐈")
            |> json_response_and_validate_schema(404) == %{"error" => "Record not found"}
   end
+
+  describe "rate limiting" do
+    test "PUT and DELETE share a per-status limit", %{conn: conn} do
+      clear_config([:rate_limit, :status_id_action], {60_000, 2})
+      user = insert(:user)
+      %{id: activity_id} = insert(:note_activity)
+      %{id: other_activity_id} = insert(:note_activity)
+      conn = prepare_conn_of_user(conn, user)
+
+      conn
+      |> put("/api/v1/pleroma/statuses/#{activity_id}/reactions/☕")
+      |> json_response_and_validate_schema(200)
+
+      conn
+      |> delete("/api/v1/pleroma/statuses/#{activity_id}/reactions/☕")
+      |> json_response_and_validate_schema(200)
+
+      assert conn
+             |> put("/api/v1/pleroma/statuses/#{activity_id}/reactions/🐈")
+             |> json_response(429) == %{"error" => "Throttled"}
+
+      conn
+      |> put("/api/v1/pleroma/statuses/#{other_activity_id}/reactions/🐈")
+      |> json_response_and_validate_schema(200)
+    end
+
+    test "PUT and DELETE count against statuses_actions", %{conn: conn} do
+      clear_config([:rate_limit, :statuses_actions], {60_000, 2})
+      user = insert(:user)
+      [first, second, third] = insert_list(3, :note_activity)
+      conn = prepare_conn_of_user(conn, user)
+
+      conn
+      |> put("/api/v1/pleroma/statuses/#{first.id}/reactions/☕")
+      |> json_response_and_validate_schema(200)
+
+      conn
+      |> delete("/api/v1/pleroma/statuses/#{first.id}/reactions/☕")
+      |> json_response_and_validate_schema(200)
+
+      assert conn
+             |> put("/api/v1/pleroma/statuses/#{second.id}/reactions/☕")
+             |> json_response(429) == %{"error" => "Throttled"}
+
+      assert conn
+             |> delete("/api/v1/pleroma/statuses/#{third.id}/reactions/☕")
+             |> json_response(429) == %{"error" => "Throttled"}
+    end
+  end
 end