diff --git a/src/server/authserver/Server/BattlenetBitStream.h b/src/server/authserver/Server/BattlenetBitStream.h
index a0bff314e8f..a59150f5327 100644
--- a/src/server/authserver/Server/BattlenetBitStream.h
+++ b/src/server/authserver/Server/BattlenetBitStream.h
@@ -138,7 +138,7 @@ namespace Battlenet
             if (!count || !data)
                 return;
 
-            if (_writePos + count > MaxSize)
+            if ((_writePos >> 3) + count > MaxSize)
                 throw BitStreamPositionException();
 
             _buffer.resize(_buffer.size() + count);