From d8c1b55b2223ee0b040ce4abfc1ae60b34f637ab Mon Sep 17 00:00:00 2001
From: cawtds <38510667+cawtds@users.noreply.github.com>
Date: Sat, 26 Apr 2025 00:21:03 +0200
Subject: [PATCH] ub fix for OOB access with gActiveBattler

---
 src/battle_controllers.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/battle_controllers.c b/src/battle_controllers.c
index 02276a7e14..cf50d4c340 100644
--- a/src/battle_controllers.c
+++ b/src/battle_controllers.c
@@ -57,6 +57,11 @@ void SetUpBattleVarsAndBirchZigzagoon(void)
     gBattleControllerExecFlags = 0;
     ClearBattleAnimationVars();
     ClearBattleMonForms();
+// UB: at the start of a battle CheckMoveLimitations is called with gActiveBattler 
+// from the previous battle, which can lead to multiple arrays being accessed out of bounds
+#ifdef UBFIX
+    gActiveBattler = 0;
+#endif
     BattleAI_HandleItemUseBeforeAISetup(0xF);
 
     if (gBattleTypeFlags & BATTLE_TYPE_FIRST_BATTLE)