diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index c731ed189..5f320bd7e 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -407,6 +407,8 @@ hb_buffer_t::move_to (unsigned int i)
     idx = i;
     return true;
   }
+  if (unlikely (in_error))
+    return false;
 
   assert (i <= out_len + (len - idx));
 
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index d6db00566..3f9d9ca9d 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -971,7 +971,7 @@ static inline bool apply_lookup (hb_apply_context_t *c,
       match_positions[j] += delta;
   }
 
-  for (unsigned int i = 0; i < lookupCount; i++)
+  for (unsigned int i = 0; i < lookupCount && !buffer->in_error; i++)
   {
     unsigned int idx = lookupRecord[i].sequenceIndex;
     if (idx >= count)