Minecraft Multiplayer – Player kick exploit

This exploit has the capability to disconnect every standard Minecraft client from a multiplayer server.
The exploit is performed by filling a shulker with high information items (such as fully written books) and then renaming the shulker in an anvil. Killing another player with this will cause the game to post a death message to the server chat feed. Minecraft chat allows renamed regular blocks to show up in chat upon a player’s death, sending the contents of the shulker to the server and every client connected to the server. This would usually allow players to hover over chat, and view the first few items within the container. However, because this shulker contains a high amount of information, when the contents are sent to your client, the information breaches Minecraft’s maximum chat information limit, thus kicking every player from the server.
This can be proven by the fact that disabling minecraft chat (in the optifine mod) will allow regular players to remain within the game. However, this does not work for the person performing the exploit and will receive an error saying that it exceeds “writerIndex(9)”. To remove the error, I simply increased the writerIndex value, allowing me to remain within the game.

https://www.youtube.com/watch?v=Tw-bUINamew