diff --git a/backport-autofit-signed-integer-overflow.patch b/backport-autofit-signed-integer-overflow.patch
new file mode 100644
index 0000000..b6ccd38
--- /dev/null
+++ b/backport-autofit-signed-integer-overflow.patch
@@ -0,0 +1,17 @@
+diff --git a/src/autofit/afloader.c b/src/autofit/afloader.c
+index af1d59a..79a6938 100644
+--- a/src/autofit/afloader.c
++++ b/src/autofit/afloader.c
+@@ -532,8 +532,10 @@
+       slot->metrics.horiBearingX = bbox.xMin;
+       slot->metrics.horiBearingY = bbox.yMax;
+ 
+-      slot->metrics.vertBearingX = FT_PIX_FLOOR( bbox.xMin + vvector.x );
+-      slot->metrics.vertBearingY = FT_PIX_FLOOR( bbox.yMax + vvector.y );
++      slot->metrics.vertBearingX = FT_PIX_FLOOR( ADD_LONG( bbox.xMin,
++                                                           vvector.x ) );
++      slot->metrics.vertBearingY = FT_PIX_FLOOR( ADD_LONG( bbox.yMax,
++                                                           vvector.y ) );
+ 
+       /* for mono-width fonts (like Andale, Courier, etc.) we need */
+       /* to keep the original rounded advance width; ditto for     */
diff --git a/install.py b/install.py
index 6982373..928546f 100755
--- a/install.py
+++ b/install.py
@@ -41,6 +41,7 @@ def move_file(src_path, dst_path):
         "backport-freetype-2.12.1-enable-funcs.patch",
         "CVE-2026-23865.patch",
         "backport-truetype-signed-integer-overflow.patch",
+        "backport-autofit-signed-integer-overflow.patch",
         "ftconfig.h"
     ]
     for file in files:
@@ -78,7 +79,8 @@ def do_patch(target_dir):
         "backport-freetype-2.10.1-debughook.patch",
         "backport-freetype-2.12.1-enable-funcs.patch",
         "CVE-2026-23865.patch",
-        "backport-truetype-signed-integer-overflow.patch"
+        "backport-truetype-signed-integer-overflow.patch",
+        "backport-autofit-signed-integer-overflow.patch"
     ]
 
     for patch in patch_file: