diff --git a/.gitignore b/.gitignore
index 998165d..b085c49 100644
--- a/.gitignore
+++ b/.gitignore
@@ -49,3 +49,4 @@
 /gtk-4.12.0.tar.xz
 /gtk-4.12.1.tar.xz
 /gtk-4.12.2.tar.xz
+/gtk-4.12.3.tar.xz
diff --git a/6437.patch b/6437.patch
deleted file mode 100644
index 8cdc522..0000000
--- a/6437.patch
+++ /dev/null
@@ -1,217 +0,0 @@
-From d8c821a85196822bc96a4a67df6831bde471758d Mon Sep 17 00:00:00 2001
-From: Michael Catanzaro <mcatanzaro@redhat.com>
-Date: Tue, 26 Sep 2023 18:47:01 -0500
-Subject: [PATCH 1/4] printoperation: fix case where operation may complete
- multiple twice
-
-If we are the final backend, then after removing ourselves there is no
-backend remaining. We will schedule the idle even if it has already been
-scheduled. This idle is required to run exactly once and executing it
-twices results in a double free that crashes loupe when printing. It
-also causes the user callback to execute twice, which could cause
-similar problems.
-
-Fixes #6122
----
- gtk/print/gtkprintoperation-unix.c | 5 ++++-
- 1 file changed, 4 insertions(+), 1 deletion(-)
-
-diff --git a/gtk/print/gtkprintoperation-unix.c b/gtk/print/gtkprintoperation-unix.c
-index db4d878e332..7a6fb04254f 100644
---- a/gtk/print/gtkprintoperation-unix.c
-+++ b/gtk/print/gtkprintoperation-unix.c
-@@ -1135,7 +1135,10 @@ printer_list_done_cb (GtkPrintBackend *backend,
-   gtk_print_backend_destroy (backend);
-   g_object_unref (backend);
- 
--  if (finder->backends == NULL)
-+  /* If there are no more backends left after removing ourselves from the list
-+   * above, then we're finished.
-+   */
-+  if (finder->backends == NULL && !finder->found_printer)
-     g_idle_add (find_printer_idle, finder);
- }
- 
--- 
-GitLab
-
-
-From dfbafdf047d95e1475806f38e3e8c2fb2db59c1d Mon Sep 17 00:00:00 2001
-From: Michael Catanzaro <mcatanzaro@redhat.com>
-Date: Tue, 26 Sep 2023 18:52:37 -0500
-Subject: [PATCH 2/4] printoperation: fix another case where operation may
- complete twice
-
-This is a little tricky. At first, I thought we had a codepath where we
-fail to schedule the idle that completes the print operation: if we take
-the gtk_print_backend_printer_list_is_done path for each printer
-backend, then printer_list_done_cb() is never executed and we never
-schedule the idle. But in fact, in this case, then backends == NULL at
-the bottom of find_printer(), and we'll schedule the idle there, so it's
-OK. Except it's not really OK, because we'll schedule it even if a
-printer was already found, resulting in the callback completing twice
-and a double free.
-
-Simplify this. Schedule the idle in find_printer() only if there are
-*initially* no backends, not also if all backends are immediately ready
-and already removed from consideration. Instead, always call
-printer_list_done_cb() for every backend in find_printer_init(). After
-the previous commit, printer_list_done_cb() will schedule the idle when
-appropriate.
-
-printer_list_done_cb() additionally disconnects signals that we did not
-connect in this codepath, but it does so using
-g_signal_handlers_disconnect_by_func, which is harmless. Otherwise, the
-only extra work it's doing is scheduling the idle, and that's exactly
-what find_printer_init() is missing.
----
- gtk/print/gtkprintoperation-unix.c | 13 +++++++------
- 1 file changed, 7 insertions(+), 6 deletions(-)
-
-diff --git a/gtk/print/gtkprintoperation-unix.c b/gtk/print/gtkprintoperation-unix.c
-index 7a6fb04254f..4d592eeb6cd 100644
---- a/gtk/print/gtkprintoperation-unix.c
-+++ b/gtk/print/gtkprintoperation-unix.c
-@@ -1165,9 +1165,7 @@ find_printer_init (PrinterFinder   *finder,
- 
-   if (gtk_print_backend_printer_list_is_done (backend))
-     {
--      finder->backends = g_list_remove (finder->backends, backend);
--      gtk_print_backend_destroy (backend);
--      g_object_unref (backend);
-+      printer_list_done_cb (backend, finder);
-     }
-   else
-     {
-@@ -1229,14 +1227,17 @@ find_printer (const char *printer,
-   if (g_module_supported ())
-     finder->backends = gtk_print_backend_load_modules ();
- 
-+  if (finder->backends == NULL)
-+    {
-+      g_idle_add (find_printer_idle, finder);
-+      return;
-+    }
-+
-   for (node = finder->backends; !finder->found_printer && node != NULL; node = next)
-     {
-       next = node->next;
-       find_printer_init (finder, GTK_PRINT_BACKEND (node->data));
-     }
--
--  if (finder->backends == NULL)
--    g_idle_add (find_printer_idle, finder);
- }
- 
- 
--- 
-GitLab
-
-
-From 653c10e8b6e90604ede1e586a8aa88e4ff46b66e Mon Sep 17 00:00:00 2001
-From: Michael Catanzaro <mcatanzaro@redhat.com>
-Date: Tue, 26 Sep 2023 19:25:41 -0500
-Subject: [PATCH 3/4] printoperation: add some assertions
-
-Let's assert that we schedule the idle callback exactly once.
-
-These assertions are not perfect because if the callback executes before
-we schedule it, then the assertion itself would be a use-after-free,
-since I'm using the PrinterFinder to track whether the callback that
-frees it has been scheduled. But in practice when using loupe's print
-dialog, I was noticing the callback scheduled twice before it was
-executed. The assertion would have caught this problem.
----
- gtk/print/gtkprintoperation-unix.c | 15 ++++++++++++---
- 1 file changed, 12 insertions(+), 3 deletions(-)
-
-diff --git a/gtk/print/gtkprintoperation-unix.c b/gtk/print/gtkprintoperation-unix.c
-index 4d592eeb6cd..ab69e1970be 100644
---- a/gtk/print/gtkprintoperation-unix.c
-+++ b/gtk/print/gtkprintoperation-unix.c
-@@ -1056,6 +1056,7 @@ gtk_print_run_page_setup_dialog_async (GtkWindow            *parent,
- struct _PrinterFinder
- {
-   gboolean found_printer;
-+  gboolean scheduled_callback;
-   GFunc func;
-   gpointer data;
-   char *printer_name;
-@@ -1088,6 +1089,14 @@ find_printer_idle (gpointer data)
-   return G_SOURCE_REMOVE;
- }
- 
-+static void
-+schedule_finder_callback (PrinterFinder *finder)
-+{
-+  g_assert (!finder->scheduled_callback);
-+  g_idle_add (find_printer_idle, finder);
-+  finder->scheduled_callback = TRUE;
-+}
-+
- static void
- printer_added_cb (GtkPrintBackend *backend,
-                   GtkPrinter      *printer,
-@@ -1120,7 +1129,7 @@ printer_added_cb (GtkPrintBackend *backend,
-     }
- 
-   if (finder->found_printer)
--    g_idle_add (find_printer_idle, finder);
-+    schedule_finder_callback (finder);
- }
- 
- static void
-@@ -1139,7 +1148,7 @@ printer_list_done_cb (GtkPrintBackend *backend,
-    * above, then we're finished.
-    */
-   if (finder->backends == NULL && !finder->found_printer)
--    g_idle_add (find_printer_idle, finder);
-+    schedule_finder_callback (finder);
- }
- 
- static void
-@@ -1229,7 +1238,7 @@ find_printer (const char *printer,
- 
-   if (finder->backends == NULL)
-     {
--      g_idle_add (find_printer_idle, finder);
-+      schedule_finder_callback (finder);
-       return;
-     }
- 
--- 
-GitLab
-
-
-From 1e2975147d307728d3ae93e44ae8d934e2dd16a9 Mon Sep 17 00:00:00 2001
-From: Michael Catanzaro <mcatanzaro@redhat.com>
-Date: Tue, 26 Sep 2023 19:28:12 -0500
-Subject: [PATCH 4/4] printoperation: fix some strange line spacing
-
----
- gtk/print/gtkprintoperation-unix.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/gtk/print/gtkprintoperation-unix.c b/gtk/print/gtkprintoperation-unix.c
-index ab69e1970be..cf52c56463b 100644
---- a/gtk/print/gtkprintoperation-unix.c
-+++ b/gtk/print/gtkprintoperation-unix.c
-@@ -1249,7 +1249,6 @@ find_printer (const char *printer,
-     }
- }
- 
--
- GtkPrintOperationResult
- _gtk_print_operation_platform_backend_run_dialog (GtkPrintOperation *op,
- 						  gboolean           show_dialog,
-@@ -1261,6 +1260,7 @@ _gtk_print_operation_platform_backend_run_dialog (GtkPrintOperation *op,
-   else
-     return gtk_print_operation_unix_run_dialog (op, show_dialog, parent, do_print);
- }
-+
- void
- _gtk_print_operation_platform_backend_run_dialog_async (GtkPrintOperation          *op,
- 							gboolean                    show_dialog,
--- 
-GitLab
-
diff --git a/gtk4.spec b/gtk4.spec
index f5f52cf..5852e9c 100644
--- a/gtk4.spec
+++ b/gtk4.spec
@@ -16,16 +16,13 @@
 %global __provides_exclude_from ^%{_libdir}/gtk-4.0
 
 Name:           gtk4
-Version:        4.12.2
+Version:        4.12.3
 Release:        %autorelease
 Summary:        GTK graphical user interface library
 
 License:        LGPL-2.0-or-later
 URL:            https://www.gtk.org
 Source0:        https://download.gnome.org/sources/gtk/4.12/gtk-%{version}.tar.xz
-# Backported from upstream
-# https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/6437
-Patch:          6437.patch
 
 BuildRequires:  cups-devel
 BuildRequires:  desktop-file-utils
diff --git a/sources b/sources
index 9b73672..7568865 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (gtk-4.12.2.tar.xz) = 5373a3c6bf434644b97c955207c80833c8f77402baca6a91b0f467b5a2fea1474e6913104ee764d61df19a8ca98c117580ad54a95cfab64113e26e8bdc3ff095
+SHA512 (gtk-4.12.3.tar.xz) = f3efa9ad340362cecd81389219092b46e3b3f7b049dd6e02aecf4ac74f64f413f0b99c23cfac854e6b0a84d9715fb832beb7e0e698fcdb90ee49a78b27d0e366