OpenComputers is a Minecraft mod that adds programmable computers and robots to the game. A user can use OpenComputers to get a Computer thread stuck in the Lua VM, which eventually blocks the Server thread, requiring the server to be forcibly shut down. This can be accomplished using any device in the mod and can be performed by anyone who can execute Lua code on them. This occurs while using the native Lua library. LuaJ appears to not have this issue. This vulnerability is fixed in 1.8.4. The GregTech: New Horizons modpack uses its own modified version of OpenComputers. They have applied the relevant patch in version 1.10.10-GTNH.

OpenComputers is a Minecraft mod that adds programmable computers and robots to the game. This issue affects every version of OpenComputers with the Internet Card feature enabled; that is, OpenComputers 1.2.0 until 1.8.3 in their most common, default configurations. If the OpenComputers mod is installed as part of a Minecraft server hosted on a popular cloud hosting provider, such as AWS, GCP and Azure, those metadata services' API endpoints are not forbidden (aka "blacklisted") by default. As such, any player can gain access to sensitive information exposed via those metadata servers, potentially allowing them to pivot or privilege escalate into the hosting provider. In addition, IPv6 addresses are not correctly filtered at all, allowing broader access into the local IPv6 network. This can allow a player on a server using an OpenComputers computer to access parts of the private IPv4 address space, as well as the whole IPv6 address space, in order to retrieve sensitive information. O…