Index: control.c
===================================================================
--- control.c.orig	2022-04-25 08:25:13 UTC
+++ control.c
@@ -775,6 +775,9 @@ control_start(struct client *c)
 
 	cs->read_event = bufferevent_new(c->fd, control_read_callback,
 	    control_write_callback, control_error_callback, c);
+	if (cs->read_event == NULL)
+		fatalx("out of memory");
+
 	bufferevent_enable(cs->read_event, EV_READ);
 
 	if (c->flags & CLIENT_CONTROLCONTROL)
@@ -782,6 +785,8 @@ control_start(struct client *c)
 	else {
 		cs->write_event = bufferevent_new(c->out_fd, NULL,
 		    control_write_callback, control_error_callback, c);
+		if (cs->write_event == NULL)
+			fatalx("out of memory");
 	}
 	bufferevent_setwatermark(cs->write_event, EV_WRITE, CONTROL_BUFFER_LOW,
 	    0);
--- file.c.orig	2022-04-25 08:25:13 UTC
+++ file.c
@@ -585,6 +585,8 @@ file_write_open(struct client_files *files, struct tmu
 
 	cf->event = bufferevent_new(cf->fd, NULL, file_write_callback,
 	    file_write_error_callback, cf);
+	if (cf->event == NULL)
+		fatalx("out of memory");
 	bufferevent_enable(cf->event, EV_WRITE);
 	goto reply;
 
@@ -744,6 +746,8 @@ file_read_open(struct client_files *files, struct tmux
 
 	cf->event = bufferevent_new(cf->fd, file_read_callback, NULL,
 	    file_read_error_callback, cf);
+	if (cf->event == NULL)
+		fatalx("out of memory");
 	bufferevent_enable(cf->event, EV_READ);
 	return;
 
--- window.c.orig	2022-04-25 08:25:14 UTC
+++ window.c
@@ -1042,6 +1042,8 @@ window_pane_set_event(struct window_pane *wp)
 
 	wp->event = bufferevent_new(wp->fd, window_pane_read_callback,
 	    NULL, window_pane_error_callback, wp);
+	if (wp->event == NULL)
+		fatalx("out of memory");
 	wp->ictx = input_init(wp, wp->event, &wp->palette);
 
 	bufferevent_enable(wp->event, EV_READ|EV_WRITE);