Log4Shell

Log4Shell is an exploit for the log4j2 library that affects Minecraft versions 1.8 through 1.18. Due to the nature of this exploit, a number of servers, including MinecraftOnline, temporarily went offline to issue patches for the issues. This exploit affects both clients and servers.

Check if your client is affected

MinecraftOnline is currently proving a free tool to check if your Java Edition 1.12.2 to 1.18.1 client is affected by the Log4Shell exploit. Connect to check.mco.re with your client to receive a message about whether or not your client is affected. If your client is not affected, congratulations! If your client is affected, please read on:

How to protect yourself

• If you're running Vanilla Minecraft, all you need to do is restart your Minecraft launcher and try again.
• If you are running Minecraft Forge, please install the latest version of Forge for 1.12.2
  • Some of your mods, like Optifine, may be incompatible with the new version of Forge. Please consult with the support website or Discord server for those mods for further instruction.
• If you are running Liteloader, please reinstall Liteloader on the new profile for Forge or Vanilla.
• If you are running some other client, please refer to your client's support website or Discord server for further instruction.

MinecraftOnline has been patched since December 10, 2021. Any players on our server will not be able to send nor receive the exploit. We still recommend ensuring your client is safe, regardless of whether or not you play on other servers.