patch 9.0.2140: [security]: use-after-free in win-enter Commit: https://github.com/vim/vim/commit/eec0c2b3a4cfab93dd8d4adaa60638d47a2bbc8a Author: Christian Brabandt <cb@256bit.org> Date: Tue Nov 28 22:03:48 2023 +0100 patch 9.0.2140: [security]: use-after-free in win-enter Problem: [security]: use-after-free in win-enter Solution: validate window pointer before calling win_enter() win_goto() may stop visual mode, if it is active. However, this may in turn trigger the ModeChanged autocommand, which could potentially free the wp pointer which was valid before now became stale and points to now freed memory. So before calling win_enter(), let's verify one more time, that the wp pointer still points to a valid window structure. Reported by @henices, thanks! Signed-off-by: Christian Brabandt <cb@256bit.org>

--- a/src/window.c
+++ b/src/window.c
@@ -5013,6 +5013,7 @@ tabpage_move(int nr)
  * Go to another window.
  * When jumping to another buffer, stop Visual mode.  Do this before
  * changing windows so we can yank the selection into the '*' register.
+ * (note: this may trigger ModeChanged autocommand!)
  * When jumping to another window on the same buffer, adjust its cursor
  * position to keep the same Visual area.
  */
@@ -5039,10 +5040,15 @@ win_goto(win_T *wp)
     }
 
     if (wp->w_buffer != curbuf)
+	// careful: triggers ModeChanged autocommand
 	reset_VIsual_and_resel();
     else if (VIsual_active)
 	wp->w_cursor = curwin->w_cursor;
 
+    // autocommand may have made wp invalid
+    if (!win_valid(wp))
+	return;
+
 #ifdef FEAT_GUI
     need_mouse_correct = TRUE;
 #endif