diff --git a/Userland/Libraries/LibWeb/HTML/Window.cpp b/Userland/Libraries/LibWeb/HTML/Window.cpp
index caab16f09e..5272ad1e98 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Window.cpp
@@ -705,27 +705,35 @@ void Window::fire_a_page_transition_event(DeprecatedFlyString const& event_name,
 }
 
 // https://html.spec.whatwg.org/multipage/webstorage.html#dom-localstorage
-JS::NonnullGCPtr<HTML::Storage> Window::local_storage()
+WebIDL::ExceptionOr<JS::NonnullGCPtr<HTML::Storage>> Window::local_storage()
 {
     // FIXME: Implement according to spec.
+    auto& vm = this->vm();
 
     static HashMap<Origin, JS::Handle<HTML::Storage>> local_storage_per_origin;
-    auto storage = local_storage_per_origin.ensure(associated_document().origin(), [this]() -> JS::Handle<HTML::Storage> {
-        return *HTML::Storage::create(realm()).release_value_but_fixme_should_propagate_errors();
-    });
-    return *storage;
+    auto storage = TRY_OR_THROW_OOM(vm, local_storage_per_origin.try_ensure(associated_document().origin(), [this]() -> ErrorOr<JS::Handle<HTML::Storage>> {
+        auto storage_or_exception = HTML::Storage::create(realm());
+        if (storage_or_exception.is_exception())
+            return Error::from_errno(ENOMEM);
+        return *storage_or_exception.release_value();
+    }));
+    return JS::NonnullGCPtr { *storage };
 }
 
 // https://html.spec.whatwg.org/multipage/webstorage.html#dom-sessionstorage
-JS::NonnullGCPtr<HTML::Storage> Window::session_storage()
+WebIDL::ExceptionOr<JS::NonnullGCPtr<HTML::Storage>> Window::session_storage()
 {
     // FIXME: Implement according to spec.
+    auto& vm = this->vm();
 
     static HashMap<Origin, JS::Handle<HTML::Storage>> session_storage_per_origin;
-    auto storage = session_storage_per_origin.ensure(associated_document().origin(), [this]() -> JS::Handle<HTML::Storage> {
-        return *HTML::Storage::create(realm()).release_value_but_fixme_should_propagate_errors();
-    });
-    return *storage;
+    auto storage = TRY_OR_THROW_OOM(vm, session_storage_per_origin.try_ensure(associated_document().origin(), [this]() -> ErrorOr<JS::Handle<HTML::Storage>> {
+        auto storage_or_exception = HTML::Storage::create(realm());
+        if (storage_or_exception.is_exception())
+            return Error::from_errno(ENOMEM);
+        return *storage_or_exception.release_value();
+    }));
+    return JS::NonnullGCPtr { *storage };
 }
 
 // https://html.spec.whatwg.org/multipage/interaction.html#transient-activation
diff --git a/Userland/Libraries/LibWeb/HTML/Window.h b/Userland/Libraries/LibWeb/HTML/Window.h
index f3f770a68f..c855239453 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.h
+++ b/Userland/Libraries/LibWeb/HTML/Window.h
@@ -115,8 +115,8 @@ public:
 
     void fire_a_page_transition_event(DeprecatedFlyString const& event_name, bool persisted);
 
-    JS::NonnullGCPtr<HTML::Storage> local_storage();
-    JS::NonnullGCPtr<HTML::Storage> session_storage();
+    WebIDL::ExceptionOr<JS::NonnullGCPtr<HTML::Storage>> local_storage();
+    WebIDL::ExceptionOr<JS::NonnullGCPtr<HTML::Storage>> session_storage();
 
     void start_an_idle_period();
 
diff --git a/Userland/Services/WebContent/ConnectionFromClient.cpp b/Userland/Services/WebContent/ConnectionFromClient.cpp
index d2d6a79db2..3e7b27ef8e 100644
--- a/Userland/Services/WebContent/ConnectionFromClient.cpp
+++ b/Userland/Services/WebContent/ConnectionFromClient.cpp
@@ -258,8 +258,8 @@ void ConnectionFromClient::debug_request(DeprecatedString const& request, Deprec
     }
 
     if (request == "dump-local-storage") {
-        if (auto* doc = page().top_level_browsing_context().active_document())
-            doc->window().local_storage()->dump();
+        if (auto* document = page().top_level_browsing_context().active_document())
+            document->window().local_storage().release_value_but_fixme_should_propagate_errors()->dump();
     }
 }
 
@@ -549,14 +549,14 @@ void ConnectionFromClient::set_window_size(Gfx::IntSize size)
 Messages::WebContentServer::GetLocalStorageEntriesResponse ConnectionFromClient::get_local_storage_entries()
 {
     auto* document = page().top_level_browsing_context().active_document();
-    auto local_storage = document->window().local_storage();
+    auto local_storage = document->window().local_storage().release_value_but_fixme_should_propagate_errors();
     return local_storage->map();
 }
 
 Messages::WebContentServer::GetSessionStorageEntriesResponse ConnectionFromClient::get_session_storage_entries()
 {
     auto* document = page().top_level_browsing_context().active_document();
-    auto session_storage = document->window().session_storage();
+    auto session_storage = document->window().session_storage().release_value_but_fixme_should_propagate_errors();
     return session_storage->map();
 }