From 035447b08f3b2db1d370422a9d8a3b53c88a2cc8 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Fri, 19 Jun 2026 08:21:55 +0000
Subject: [PATCH] Do not dereference the current window if it is NULL (can be
 if the notification fires after session is destroyed). GitHub issue 5244 from
 Ben Maurer.

---
 control-notify.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/control-notify.c b/control-notify.c
index 151f959d..021f9884 100644
--- a/control-notify.c
+++ b/control-notify.c
@@ -224,6 +224,14 @@ control_notify_session_window_changed(struct session *s)
 {
 	struct client	*c;
 
+	/*
+	 * A deferred session-window-changed notification can fire after the
+	 * session has been destroyed (which sets curw to NULL) but is kept
+	 * alive by the notification's reference. Skip the notification.
+	 */
+	if (s->curw == NULL)
+		return;
+
 	TAILQ_FOREACH(c, &clients, entry) {
 		if (!CONTROL_SHOULD_NOTIFY_CLIENT(c))
 			continue;