diff --git a/src/truetype/ttgxvar.c b/src/truetype/ttgxvar.c
index 7d67d5f8d..095a72055 100644
--- a/src/truetype/ttgxvar.c
+++ b/src/truetype/ttgxvar.c
@@ -1028,6 +1028,9 @@
     if ( innerIndex >= varData->itemCount )
       return 0; /* Out of range. */
 
+    if ( varData->regionIdxCount == 0 )
+      return 0; /* Avoid "applying zero offset to null pointer". */
+
     if ( varData->regionIdxCount < 16 )
     {
       deltaSet = deltaSetStack;