diff --git a/ChangeLog b/ChangeLog
index 04b4fbd..b10dffb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-27  Ben Wagner  <bungeman@google.com>
+
+	[truetype Fix numeric overflow (#55103).
+
+	* src/truetype/ttgload.c (compute_glyph_metrics): Use `SUB_LONG'.
+
 2018-11-18  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
 	[builds] Belated DLL support with vc2002-vc2008.
diff --git a/src/truetype/ttgload.c b/src/truetype/ttgload.c
index 3028622..1d84450 100644
--- a/src/truetype/ttgload.c
+++ b/src/truetype/ttgload.c
@@ -2160,7 +2160,7 @@
 
     glyph->metrics.horiBearingX = bbox.xMin;
     glyph->metrics.horiBearingY = bbox.yMax;
-    glyph->metrics.horiAdvance  = loader->pp2.x - loader->pp1.x;
+    glyph->metrics.horiAdvance  = SUB_LONG(loader->pp2.x, loader->pp1.x);
 
     /* Adjust advance width to the value contained in the hdmx table   */
     /* unless FT_LOAD_COMPUTE_METRICS is set or backward compatibility */