diff --git a/src/OT/glyf/SimpleGlyph.hh b/src/OT/glyf/SimpleGlyph.hh
index 93b457cb0..b03b172fc 100644
--- a/src/OT/glyf/SimpleGlyph.hh
+++ b/src/OT/glyf/SimpleGlyph.hh
@@ -171,6 +171,7 @@ struct SimpleGlyph
     const HBUINT8 *p = &StructAtOffset<HBUINT8> (&endPtsOfContours[num_contours + 1],
 						 endPtsOfContours[num_contours]);
 
+    if (unlikely ((const char *) p < bytes.arrayZ)) return false; /* Unlikely overflow */
     const HBUINT8 *end = (const HBUINT8 *) (bytes.arrayZ + bytes.length);
 
     /* Read flags */