Last night a player in my small server started to disconnect with this error message. I suppose he uses some modded client and in some way it tries to send strange stuff to server. Server does not crash - it only kicks player.

[14:04:48] [Server thread/INFO]: aleko22 lost connection: Internal Exception: io.netty.handler.codec.DecoderException: java.lang.IndexOutOfBoundsException: readerIndex(10) + length(1) exceeds writerIndex(10): UnpooledHeapByteBuf(ridx: 10, widx: 10, cap: 10)