--- sys/kern/tty.c.orig
+++ sys/kern/tty.c
@@ -44,6 +44,7 @@
 #ifdef COMPAT_43TTY
 #include <sys/ioctl_compat.h>
 #endif /* COMPAT_43TTY */
+#include <sys/jail.h>
 #include <sys/kernel.h>
 #include <sys/limits.h>
 #include <sys/malloc.h>
@@ -1308,9 +1309,11 @@
 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
 {
 	unsigned long lsize;
+	struct thread *td = curthread;
 	struct xtty *xtlist, *xt;
 	struct tty *tp;
-	int error;
+	struct proc *p;
+	int cansee, error;
 
 	sx_slock(&tty_list_sx);
 	lsize = tty_list_count * sizeof(struct xtty);
@@ -1323,13 +1326,28 @@
 
 	TAILQ_FOREACH(tp, &tty_list, t_list) {
 		tty_lock(tp);
-		tty_to_xtty(tp, xt);
+		if (tp->t_session != NULL) {
+			p = tp->t_session->s_leader;
+			PROC_LOCK(p);
+			cansee = (p_cansee(td, p) == 0);
+			PROC_UNLOCK(p);
+		} else {
+			cansee = !jailed(td->td_ucred);
+		}
+		if (cansee) {
+			tty_to_xtty(tp, xt);
+			xt++;
+		}
 		tty_unlock(tp);
-		xt++;
 	}
 	sx_sunlock(&tty_list_sx);
 
-	error = SYSCTL_OUT(req, xtlist, lsize);
+	lsize = (xt - xtlist) * sizeof(struct xtty);
+	if (lsize > 0) {
+		error = SYSCTL_OUT(req, xtlist, lsize);
+	} else {
+		error = 0;
+	}
 	free(xtlist, M_TTY);
 	return (error);
 }