--- /n/sources/plan9/sys/src/cmd/upas/smtp/smtp.c	Fri Nov  8 22:54:09 2013
+++ /sys/src/cmd/upas/smtp/smtp.c	Tue Jun 23 00:00:00 2026
@@ -816,7 +816,7 @@
 
 	/* parse the '!' format address */
 	buf = s_new();
-	for(i = 0; addr; i++){
+	for(i = 0; addr && i < nelem(field); i++){
 		field[i] = addr;
 		addr = strchr(addr, '!');
 		if(addr)