diff -Nur rush-1.8.orig/lib/wordsplit.c rush-1.8/lib/wordsplit.c
--- rush-1.8.orig/lib/wordsplit.c	2016-08-18 20:11:43.000000000 +0200
+++ rush-1.8/lib/wordsplit.c	2016-11-14 14:37:02.976177414 +0100
@@ -2330,7 +2330,7 @@
       break;
 
     default:
-      wsp->ws_error (wordsplit_strerror (wsp));
+      wsp->ws_error ("%s", wordsplit_strerror (wsp));
     }
 }