diff --git a/tests/helpers.h b/tests/helpers.h
index 8be1d40..efc7ea5 100644
--- a/tests/helpers.h
+++ b/tests/helpers.h
@@ -66,7 +66,7 @@ setup_allocator(void)
     do { \
         call; \
         if (cork_error_occurred()) { \
-            ck_abort_msg(cork_error_message()); \
+            ck_abort_msg("%s", cork_error_message()); \
         } \
     } while (0)