From bda3b1078ac357b805156a8802a0649f7021716e Mon Sep 17 00:00:00 2001
From: Loki <lokirautio@gmail.com>
Date: Mon, 9 Mar 2026 06:53:08 -0500
Subject: Port over RCE Patches from LCEMP (#1023)

* LCEMP RCE Fixes WIP

Based on https://github.com/LCEMP/LCEMP/commit/d017bfc30a68888bf5c79b23cf5c4f607cf828bf

* Update to LCEMP's ByteArrayIO version

Fixes compilation since ours was missing some revisions from LCEMP

* Add additional safety checks missed in first pass

* Remove duplicate recipe count check
---
 Minecraft.World/BlockRegionUpdatePacket.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'Minecraft.World/BlockRegionUpdatePacket.cpp')

diff --git a/Minecraft.World/BlockRegionUpdatePacket.cpp b/Minecraft.World/BlockRegionUpdatePacket.cpp
index 730ce3ed..b91cf4f8 100644
--- a/Minecraft.World/BlockRegionUpdatePacket.cpp
+++ b/Minecraft.World/BlockRegionUpdatePacket.cpp
@@ -105,6 +105,12 @@ void BlockRegionUpdatePacket::read(DataInputStream *dis) //throws IOException
 	levelIdx = ( size >> 30 ) & 3;
 	size &= 0x3fffffff;
 
+	const int MAX_COMPRESSED_CHUNK_SIZE = 5 * 1024 * 1024;
+    if (size < 0 || size > MAX_COMPRESSED_CHUNK_SIZE)
+    {
+        size = 0;
+    }
+
 	if(size == 0)
 	{
 		buffer = byteArray();
-- 
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