diff -ru rxvt-unicode-9.22/src/command.C rxvt-unicode-9.22-patched/src/command.C
--- rxvt-unicode-9.22/src/command.C	2016-01-18 20:35:08.000000000 +0100
+++ rxvt-unicode-9.22-patched/src/command.C	2017-04-28 09:52:35.440245607 +0200
@@ -2868,7 +2868,7 @@
   i = ch - CSI_ICH;
   ndef = get_byte_array_bit (csi_defaults, i);
   for (p = 0; p < nargs; p++)
-    if (arg[p] == -1)
+    if (arg[p] < 0 || arg[p] > 30000)
       arg[p] = ndef;
 
   /*