diff -Naur xc.orig/programs/xdm/sessreg.c xc/programs/xdm/sessreg.c
--- xc.orig/programs/xdm/sessreg.c	2004-04-23 21:54:42.000000000 +0200
+++ xc/programs/xdm/sessreg.c	2004-10-13 22:07:40.000000000 +0200
@@ -359,6 +359,7 @@
 static void
 set_utmp (struct utmp *u, char *line, char *user, char *host, Time_t date, int addp)
 {
+	bzero (u, sizeof (*u));
 	if (line)
 		(void) strncpy (u->ut_line, line, sizeof (u->ut_line));
 	else