From 7c986a3a099bfbfdcd7232ee3b02e38423ed285d Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 13 Jul 2026 14:48:25 +0200
Subject: [PATCH] Fix crash when encoding CJK characters from UTF-16  into
 UTF-8

#4180
---
 Source/Engine/Utilities/StringConverter.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Source/Engine/Utilities/StringConverter.h b/Source/Engine/Utilities/StringConverter.h
index 9e6fa9569..331b5863b 100644
--- a/Source/Engine/Utilities/StringConverter.h
+++ b/Source/Engine/Utilities/StringConverter.h
@@ -86,7 +86,8 @@ public:
     StringAsUTF8(const Char* text, int32 length)
     {
         int32 lengthUtf8;
-        if (length + 1 < InlinedSize)
+        // UTF-8 can use up to 3 bytes per UTF-16 code unit
+        if (length * 3 + 1 < InlinedSize)
         {
             StringUtils::ConvertUTF162UTF8(text, this->_inlined, length, lengthUtf8);
             this->_inlined[lengthUtf8] = 0;