From 940f395e3e2b4df1f16d3457c9930f1c87bf1e18 Mon Sep 17 00:00:00 2001
From: Wouter Gritter <wouter@gritter.nl>
Date: Tue, 1 Sep 2026 13:19:46 +0200
Subject: [PATCH] Use correct minimum ClientSettings packet length for older
 protocol versions

For correctness's sake: in practice this bug never got triggered because `locale` is almost always a string of length 5+ ("en_us").
---
 .../protocol/packet/ClientSettingsPacket.java | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ClientSettingsPacket.java b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ClientSettingsPacket.java
index b8b60a9f..7e6600cc 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ClientSettingsPacket.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ClientSettingsPacket.java
@@ -213,7 +213,34 @@ public class ClientSettingsPacket implements MinecraftPacket {
 
   @Override
   public int decodeExpectedMinLength(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
-    return 1 + 0 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1;
+    int minLength = 1 // locale
+            + 1       // viewDistance
+            + 1       // chatVisibility
+            + 1;      // chatColors
+
+    if (version.noGreaterThan(ProtocolVersion.MINECRAFT_1_7_6)) {
+      minLength += 1; // difficulty
+    }
+
+    minLength += 1; // skinParts
+
+    if (version.noLessThan(ProtocolVersion.MINECRAFT_1_9)) {
+      minLength += 1; // mainHand
+
+      if (version.noLessThan(ProtocolVersion.MINECRAFT_1_17)) {
+        minLength += 1; // textFilteringEnabled
+
+        if (version.noLessThan(ProtocolVersion.MINECRAFT_1_18)) {
+          minLength += 1; // clientListingAllowed
+
+          if (version.noLessThan(ProtocolVersion.MINECRAFT_1_21_2)) {
+            minLength += 1; // particleStatus
+          }
+        }
+      }
+    }
+
+    return minLength;
   }
 
   @Override