diff --git a/src/hb-ot-cff-common.hh b/src/hb-ot-cff-common.hh
index bde4676df..379a13443 100644
--- a/src/hb-ot-cff-common.hh
+++ b/src/hb-ot-cff-common.hh
@@ -287,6 +287,7 @@ struct CFFIndex
 
   public:
   COUNT		count;		/* Number of object data. Note there are (count+1) offsets */
+  private:
   HBUINT8	offSize;	/* The byte size of each offset in the offsets array. */
   HBUINT8	offsets[HB_VAR_ARRAY];
 				/* The array of (count + 1) offsets into objects array (1-base). */