diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5a1f065999638..36eb51a5145d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,9 +5,15 @@ All notable changes to this project will be documented in this file.
 
 ## End of life notice
 
-**The 4.0.x branch will not receive any update after 2023-10-31.**
+**The 4.0.x branch has reached its end of life and will not receive any further update.**
 This means that no security fix will be made available for this branch after this date, and you will need to update to a more recent version (such as the 4.2.x branch) to receive security fixes.
 
+## [4.0.13] - 2024-02-01
+
+### Security
+
+- Fix insufficient origin validation (CVE-2024-23832, [GHSA-3fjr-858r-92rw](https://github.com/mastodon/mastodon/security/advisories/GHSA-3fjr-858r-92rw))
+
 ## [4.0.12] - 2023-10-10
 
 ### Changed
diff --git a/SECURITY.md b/SECURITY.md
index ebb05ba2cc2c3..5091fb9e60a47 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -13,6 +13,5 @@ A "vulnerability in Mastodon" is a vulnerability in the code distributed through
 | Version | Supported          |
 | ------- | ------------------ |
 | 4.1.x   | Yes                |
-| 4.0.x   | Until 2023-10-31   |
-| 3.5.x   | Until 2023-12-31   |
-| < 3.5   | No                 |
+| 4.0.x   | No                 |
+| < 4.0   | No                 |
diff --git a/app/controllers/concerns/signature_verification.rb b/app/controllers/concerns/signature_verification.rb
index 2394574b3bede..ecdccad4f7b96 100644
--- a/app/controllers/concerns/signature_verification.rb
+++ b/app/controllers/concerns/signature_verification.rb
@@ -246,7 +246,7 @@ def actor_from_key_id(key_id)
       stoplight_wrap_request { ResolveAccountService.new.call(key_id.gsub(/\Aacct:/, ''), suppress_errors: false) }
     elsif !ActivityPub::TagManager.instance.local_uri?(key_id)
       account   = ActivityPub::TagManager.instance.uri_to_actor(key_id)
-      account ||= stoplight_wrap_request { ActivityPub::FetchRemoteKeyService.new.call(key_id, id: false, suppress_errors: false) }
+      account ||= stoplight_wrap_request { ActivityPub::FetchRemoteKeyService.new.call(key_id, suppress_errors: false) }
       account
     end
   rescue Mastodon::PrivateNetworkAddressError => e
diff --git a/app/helpers/jsonld_helper.rb b/app/helpers/jsonld_helper.rb
index 102e4b13281ad..18314d99f0a4a 100644
--- a/app/helpers/jsonld_helper.rb
+++ b/app/helpers/jsonld_helper.rb
@@ -157,8 +157,8 @@ def safe_for_forwarding?(original, compacted)
     end
   end
 
-  def fetch_resource(uri, id, on_behalf_of = nil)
-    unless id
+  def fetch_resource(uri, id_is_known, on_behalf_of = nil)
+    unless id_is_known
       json = fetch_resource_without_id_validation(uri, on_behalf_of)
 
       return if !json.is_a?(Hash) || unsupported_uri_scheme?(json['id'])
diff --git a/app/lib/activitypub/activity.rb b/app/lib/activitypub/activity.rb
index f4c67cccd733a..e11ce49d97faa 100644
--- a/app/lib/activitypub/activity.rb
+++ b/app/lib/activitypub/activity.rb
@@ -152,7 +152,9 @@ def follow_from_object
   def fetch_remote_original_status
     if object_uri.start_with?('http')
       return if ActivityPub::TagManager.instance.local_uri?(object_uri)
-      ActivityPub::FetchRemoteStatusService.new.call(object_uri, id: true, on_behalf_of: @account.followers.local.first)
+
+
+      ActivityPub::FetchRemoteStatusService.new.call(object_uri, on_behalf_of: @account.followers.local.first)
     elsif @object['url'].present?
       ::FetchRemoteStatusService.new.call(@object['url'])
     end
diff --git a/app/lib/activitypub/linked_data_signature.rb b/app/lib/activitypub/linked_data_signature.rb
index f90adaf6c5fd3..15c5d6bb8b931 100644
--- a/app/lib/activitypub/linked_data_signature.rb
+++ b/app/lib/activitypub/linked_data_signature.rb
@@ -19,7 +19,7 @@ def verify_actor!
     return unless type == 'RsaSignature2017'
 
     creator   = ActivityPub::TagManager.instance.uri_to_actor(creator_uri)
-    creator ||= ActivityPub::FetchRemoteKeyService.new.call(creator_uri, id: false)
+    creator ||= ActivityPub::FetchRemoteKeyService.new.call(creator_uri)
 
     return if creator.nil?
 
diff --git a/app/services/activitypub/fetch_remote_account_service.rb b/app/services/activitypub/fetch_remote_account_service.rb
index ca7a8c6ca8930..744228645e6b7 100644
--- a/app/services/activitypub/fetch_remote_account_service.rb
+++ b/app/services/activitypub/fetch_remote_account_service.rb
@@ -2,7 +2,7 @@
 
 class ActivityPub::FetchRemoteAccountService < ActivityPub::FetchRemoteActorService
   # Does a WebFinger roundtrip on each call, unless `only_key` is true
-  def call(uri, id: true, prefetched_body: nil, break_on_redirect: false, only_key: false, suppress_errors: true)
+  def call(uri, prefetched_body: nil, break_on_redirect: false, only_key: false, suppress_errors: true)
     actor = super
     return actor if actor.nil? || actor.is_a?(Account)
 
diff --git a/app/services/activitypub/fetch_remote_actor_service.rb b/app/services/activitypub/fetch_remote_actor_service.rb
index db09c38d82697..bab2965ec45e5 100644
--- a/app/services/activitypub/fetch_remote_actor_service.rb
+++ b/app/services/activitypub/fetch_remote_actor_service.rb
@@ -10,15 +10,15 @@ class Error < StandardError; end
   SUPPORTED_TYPES = %w(Application Group Organization Person Service).freeze
 
   # Does a WebFinger roundtrip on each call, unless `only_key` is true
-  def call(uri, id: true, prefetched_body: nil, break_on_redirect: false, only_key: false, suppress_errors: true)
+  def call(uri, prefetched_body: nil, break_on_redirect: false, only_key: false, suppress_errors: true)
     return if domain_not_allowed?(uri)
     return ActivityPub::TagManager.instance.uri_to_actor(uri) if ActivityPub::TagManager.instance.local_uri?(uri)
 
     @json = begin
       if prefetched_body.nil?
-        fetch_resource(uri, id)
+        fetch_resource(uri, true)
       else
-        body_to_json(prefetched_body, compare_id: id ? uri : nil)
+        body_to_json(prefetched_body, compare_id: uri)
       end
     rescue Oj::ParseError
       raise Error, "Error parsing JSON-LD document #{uri}"
diff --git a/app/services/activitypub/fetch_remote_key_service.rb b/app/services/activitypub/fetch_remote_key_service.rb
index 32e82b47a58d6..1f671849236cd 100644
--- a/app/services/activitypub/fetch_remote_key_service.rb
+++ b/app/services/activitypub/fetch_remote_key_service.rb
@@ -6,23 +6,10 @@ class ActivityPub::FetchRemoteKeyService < BaseService
   class Error < StandardError; end
 
   # Returns actor that owns the key
-  def call(uri, id: true, prefetched_body: nil, suppress_errors: true)
+  def call(uri, suppress_errors: true)
     raise Error, 'No key URI given' if uri.blank?
 
-    if prefetched_body.nil?
-      if id
-        @json = fetch_resource_without_id_validation(uri)
-        if actor_type?
-          @json = fetch_resource(@json['id'], true)
-        elsif uri != @json['id']
-          raise Error, "Fetched URI #{uri} has wrong id #{@json['id']}"
-        end
-      else
-        @json = fetch_resource(uri, id)
-      end
-    else
-      @json = body_to_json(prefetched_body, compare_id: id ? uri : nil)
-    end
+    @json = fetch_resource(uri, false)
 
     raise Error, "Unable to fetch key JSON at #{uri}" if @json.nil?
     raise Error, "Unsupported JSON-LD context for document #{uri}" unless supported_context?(@json)
diff --git a/app/services/activitypub/fetch_remote_status_service.rb b/app/services/activitypub/fetch_remote_status_service.rb
index 80309824509a4..d9227d300ef29 100644
--- a/app/services/activitypub/fetch_remote_status_service.rb
+++ b/app/services/activitypub/fetch_remote_status_service.rb
@@ -4,12 +4,12 @@ class ActivityPub::FetchRemoteStatusService < BaseService
   include JsonLdHelper
 
   # Should be called when uri has already been checked for locality
-  def call(uri, id: true, prefetched_body: nil, on_behalf_of: nil)
+  def call(uri, prefetched_body: nil, on_behalf_of: nil)
     @json = begin
       if prefetched_body.nil?
-        fetch_resource(uri, id, on_behalf_of)
+        fetch_resource(uri, true, on_behalf_of)
       else
-        body_to_json(prefetched_body, compare_id: id ? uri : nil)
+        body_to_json(prefetched_body, compare_id: uri)
       end
     end
 
@@ -52,7 +52,7 @@ def trustworthy_attribution?(uri, attributed_to)
 
   def account_from_uri(uri)
     actor = ActivityPub::TagManager.instance.uri_to_resource(uri, Account)
-    actor = ActivityPub::FetchRemoteAccountService.new.call(uri, id: true) if actor.nil? || actor.possibly_stale?
+    actor = ActivityPub::FetchRemoteAccountService.new.call(uri) if actor.nil? || actor.possibly_stale?
     actor
   end
 
diff --git a/app/services/activitypub/process_account_service.rb b/app/services/activitypub/process_account_service.rb
index 16731c5146fb5..afcb1222a92c4 100644
--- a/app/services/activitypub/process_account_service.rb
+++ b/app/services/activitypub/process_account_service.rb
@@ -257,7 +257,7 @@ def collection_info(type)
 
   def moved_account
     account   = ActivityPub::TagManager.instance.uri_to_resource(@json['movedTo'], Account)
-    account ||= ActivityPub::FetchRemoteAccountService.new.call(@json['movedTo'], id: true, break_on_redirect: true)
+    account ||= ActivityPub::FetchRemoteAccountService.new.call(@json['movedTo'], break_on_redirect: true)
     account
   end
 
diff --git a/app/services/fetch_resource_service.rb b/app/services/fetch_resource_service.rb
index 73204e55db0c4..e1af234785211 100644
--- a/app/services/fetch_resource_service.rb
+++ b/app/services/fetch_resource_service.rb
@@ -47,7 +47,15 @@ def process_response(response, terminal = false)
       body = response.body_with_limit
       json = body_to_json(body)
 
-      [json['id'], { prefetched_body: body, id: true }] if supported_context?(json) && (equals_or_includes_any?(json['type'], ActivityPub::FetchRemoteActorService::SUPPORTED_TYPES) || expected_type?(json))
+      return unless supported_context?(json) && (equals_or_includes_any?(json['type'], ActivityPub::FetchRemoteActorService::SUPPORTED_TYPES) || expected_type?(json))
+
+      if json['id'] != @url
+        return if terminal
+
+        return process(json['id'], terminal: true)
+      end
+
+      [@url, { prefetched_body: body }]
     elsif !terminal
       link_header = response['Link'] && parse_link_header(response)
 
diff --git a/docker-compose.yml b/docker-compose.yml
index db2f81d203946..513c5dea73cc5 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -56,7 +56,7 @@ services:
 
   web:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.0.12
+    image: ghcr.io/mastodon/mastodon:v4.0.13
     restart: always
     env_file: .env.production
     command: bash -c "rm -f /mastodon/tmp/pids/server.pid; bundle exec rails s -p 3000"
@@ -77,7 +77,7 @@ services:
 
   streaming:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.0.12
+    image: ghcr.io/mastodon/mastodon:v4.0.13
     restart: always
     env_file: .env.production
     command: node ./streaming
@@ -95,7 +95,7 @@ services:
 
   sidekiq:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.0.12
+    image: ghcr.io/mastodon/mastodon:v4.0.13
     restart: always
     env_file: .env.production
     command: bundle exec sidekiq
diff --git a/lib/mastodon/version.rb b/lib/mastodon/version.rb
index d586fa9e3a90d..ca2966badc7d4 100644
--- a/lib/mastodon/version.rb
+++ b/lib/mastodon/version.rb
@@ -13,7 +13,7 @@ def minor
     end
 
     def patch
-      12
+      13
     end
 
     def flags
diff --git a/spec/services/activitypub/fetch_remote_account_service_spec.rb b/spec/services/activitypub/fetch_remote_account_service_spec.rb
index ec6f1f41d8f6c..9ee2c15248069 100644
--- a/spec/services/activitypub/fetch_remote_account_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_account_service_spec.rb
@@ -16,7 +16,7 @@
   end
 
   describe '#call' do
-    let(:account) { subject.call('https://example.com/alice', id: true) }
+    let(:account) { subject.call('https://example.com/alice') }
 
     shared_examples 'sets profile data' do
       it 'returns an account' do
diff --git a/spec/services/activitypub/fetch_remote_actor_service_spec.rb b/spec/services/activitypub/fetch_remote_actor_service_spec.rb
index 20117c66d0476..56805b3325476 100644
--- a/spec/services/activitypub/fetch_remote_actor_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_actor_service_spec.rb
@@ -16,7 +16,7 @@
   end
 
   describe '#call' do
-    let(:account) { subject.call('https://example.com/alice', id: true) }
+    let(:account) { subject.call('https://example.com/alice') }
 
     shared_examples 'sets profile data' do
       it 'returns an account' do
diff --git a/spec/services/activitypub/fetch_remote_key_service_spec.rb b/spec/services/activitypub/fetch_remote_key_service_spec.rb
index 3186c4270d7e3..9c818d12c0d63 100644
--- a/spec/services/activitypub/fetch_remote_key_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_key_service_spec.rb
@@ -43,7 +43,7 @@
   end
 
   describe '#call' do
-    let(:account) { subject.call(public_key_id, id: false) }
+    let(:account) { subject.call(public_key_id) }
 
     context 'when the key is a sub-object from the actor' do
       before do
diff --git a/spec/services/fetch_resource_service_spec.rb b/spec/services/fetch_resource_service_spec.rb
index c0c96ab69c95f..412c410575fd3 100644
--- a/spec/services/fetch_resource_service_spec.rb
+++ b/spec/services/fetch_resource_service_spec.rb
@@ -54,7 +54,7 @@
 
       let(:json) do
         {
-          id: 1,
+          id: 'http://example.com/foo',
           '@context': ActivityPub::TagManager::CONTEXT,
           type: 'Note',
         }.to_json
@@ -79,14 +79,14 @@
         let(:content_type) { 'application/activity+json; charset=utf-8' }
         let(:body) { json }
 
-        it { is_expected.to eq [1, { prefetched_body: body, id: true }] }
+        it { is_expected.to eq ['http://example.com/foo', { prefetched_body: body }] }
       end
 
       context 'when content type is ld+json with profile' do
         let(:content_type) { 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"' }
         let(:body) { json }
 
-        it { is_expected.to eq [1, { prefetched_body: body, id: true }] }
+        it { is_expected.to eq ['http://example.com/foo', { prefetched_body: body }] }
       end
 
       before do
@@ -97,14 +97,14 @@
       context 'when link header is present' do
         let(:headers) { { 'Link' => '<http://example.com/foo>; rel="alternate"; type="application/activity+json"', } }
 
-        it { is_expected.to eq [1, { prefetched_body: json, id: true }] }
+        it { is_expected.to eq ['http://example.com/foo', { prefetched_body: json }] }
       end
 
       context 'when content type is text/html' do
         let(:content_type) { 'text/html' }
         let(:body) { '<html><head><link rel="alternate" href="http://example.com/foo" type="application/activity+json"/></head></html>' }
 
-        it { is_expected.to eq [1, { prefetched_body: json, id: true }] }
+        it { is_expected.to eq ['http://example.com/foo', { prefetched_body: json }] }
       end
     end
   end
diff --git a/spec/services/resolve_url_service_spec.rb b/spec/services/resolve_url_service_spec.rb
index ab5b50b765058..85a672524878f 100644
--- a/spec/services/resolve_url_service_spec.rb
+++ b/spec/services/resolve_url_service_spec.rb
@@ -139,6 +139,7 @@
         stub_request(:get, url).to_return(status: 302, headers: { 'Location' => status_url })
         body = ActiveModelSerializers::SerializableResource.new(status, serializer: ActivityPub::NoteSerializer, adapter: ActivityPub::Adapter).to_json
         stub_request(:get, status_url).to_return(body: body, headers: { 'Content-Type' => 'application/activity+json' })
+        stub_request(:get, uri).to_return(body: body, headers: { 'Content-Type' => 'application/activity+json' })
       end
 
       it 'returns status by url' do