diff --git a/Tests/images/psd-oob-write-x.psd b/Tests/images/psd-oob-write-x.psd
new file mode 100644
index 000000000..86359f4cb
Binary files /dev/null and b/Tests/images/psd-oob-write-x.psd differ
diff --git a/Tests/images/psd-oob-write-y.psd b/Tests/images/psd-oob-write-y.psd
new file mode 100644
index 000000000..73498266a
Binary files /dev/null and b/Tests/images/psd-oob-write-y.psd differ
diff --git a/Tests/images/psd-oob-write.psd b/Tests/images/psd-oob-write.psd
new file mode 100644
index 000000000..65a4472cf
Binary files /dev/null and b/Tests/images/psd-oob-write.psd differ
diff --git a/Tests/test_file_psd.py b/Tests/test_file_psd.py
index 8f2ca58a6..8a2636dfe 100644
--- a/Tests/test_file_psd.py
+++ b/Tests/test_file_psd.py
@@ -182,3 +182,20 @@ def test_layer_crashes(test_file: str) -> None:
         assert isinstance(im, PsdImagePlugin.PsdImageFile)
         with pytest.raises(SyntaxError):
             im.layers
+
+
+@pytest.mark.parametrize(
+    "test_file",
+    [
+        "Tests/images/psd-oob-write.psd",
+        "Tests/images/psd-oob-write-x.psd",
+        "Tests/images/psd-oob-write-y.psd",
+    ],
+)
+def test_bounds_crash(test_file: str) -> None:
+    with Image.open(test_file) as im:
+        assert isinstance(im, PsdImagePlugin.PsdImageFile)
+        im.seek(im.n_frames)
+
+        with pytest.raises(ValueError):
+            im.load()
diff --git a/Tests/test_imagefile.py b/Tests/test_imagefile.py
index 8a0abbd39..6656ee506 100644
--- a/Tests/test_imagefile.py
+++ b/Tests/test_imagefile.py
@@ -163,6 +163,13 @@ class TestImageFile:
             with pytest.raises(ValueError, match="Tile offset cannot be negative"):
                 im.load()
 
+    @pytest.mark.parametrize("xy", ((-1, 0), (0, -1)))
+    def test_negative_tile_extents(self, xy: tuple[int, int]) -> None:
+        im = Image.new("1", (1, 1))
+        fp = BytesIO()
+        with pytest.raises(SystemError, match="tile cannot extend outside image"):
+            ImageFile._save(im, fp, [ImageFile._Tile("raw", xy + (1, 1), 0, "1")])
+
     def test_no_format(self) -> None:
         buf = BytesIO(b"\x00" * 255)
 
diff --git a/docs/releasenotes/12.1.1.rst b/docs/releasenotes/12.1.1.rst
new file mode 100644
index 000000000..9c119ceb8
--- /dev/null
+++ b/docs/releasenotes/12.1.1.rst
@@ -0,0 +1,24 @@
+12.1.1
+------
+
+Security
+========
+
+:cve:`2021-25289`: Fix OOB write with invalid tile extents
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Check that tile extents do not use negative x or y offsets when decoding or encoding,
+and raise an error if they do, rather than allowing an OOB write.
+
+An out-of-bounds write may be triggered when opening a specially crafted PSD image.
+This only affects Pillow >= 10.3.0. Reported by
+`Yarden Porat <https://github.com/yardenporat353>`__.
+
+Other changes
+=============
+
+Patch libavif for svt-av1 4.0 compatibility
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A patch has been added to ``depends/install_libavif.sh``, to allow libavif 1.3.0 to be
+compatible with the recently released svt-av1 4.0.0.
diff --git a/docs/releasenotes/index.rst b/docs/releasenotes/index.rst
index 4b25bb6a2..690be2072 100644
--- a/docs/releasenotes/index.rst
+++ b/docs/releasenotes/index.rst
@@ -15,6 +15,7 @@ expected to be backported to earlier versions.
   :maxdepth: 2
 
   versioning
+  12.1.1
   12.1.0
   12.0.0
   11.3.0
diff --git a/src/decode.c b/src/decode.c
index 051623ed4..7ec461c0e 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -186,7 +186,8 @@ _setimage(ImagingDecoderObject *decoder, PyObject *args) {
         state->ysize = y1 - y0;
     }
 
-    if (state->xsize <= 0 || state->xsize + state->xoff > (int)im->xsize ||
+    if (state->xoff < 0 || state->xsize <= 0 ||
+        state->xsize + state->xoff > (int)im->xsize || state->yoff < 0 ||
         state->ysize <= 0 || state->ysize + state->yoff > (int)im->ysize) {
         PyErr_SetString(PyExc_ValueError, "tile cannot extend outside image");
         return NULL;
diff --git a/src/encode.c b/src/encode.c
index 513309c8d..06e4a0893 100644
--- a/src/encode.c
+++ b/src/encode.c
@@ -254,7 +254,8 @@ _setimage(ImagingEncoderObject *encoder, PyObject *args) {
         state->ysize = y1 - y0;
     }
 
-    if (state->xsize <= 0 || state->xsize + state->xoff > im->xsize ||
+    if (state->xoff < 0 || state->xsize <= 0 ||
+        state->xsize + state->xoff > im->xsize || state->yoff < 0 ||
         state->ysize <= 0 || state->ysize + state->yoff > im->ysize) {
         PyErr_SetString(PyExc_SystemError, "tile cannot extend outside image");
         return NULL;