diff --git a/h_malloc.c b/h_malloc.c
index 507088c..dedd0bb 100644
--- a/h_malloc.c
+++ b/h_malloc.c
@@ -1604,7 +1604,7 @@ EXPORT size_t h_malloc_object_size(void *p) {
     }
 
     if (unlikely(slab_region_start == NULL)) {
-        return 0;
+        return SIZE_MAX;
     }
 
     thread_unseal_metadata();