--- rxvt-2.7.10/src/command.c	2003-03-26 07:01:23.000000000 +0100
+++ rxvt-2.7.10-patched/src/command.c	2017-04-27 12:06:05.682072274 +0200
@@ -2096,7 +2096,7 @@
     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;
 
 #ifdef DEBUG_CMD