mojira.dev
MC-202760

Area effect cloud does not enforce a maximum radius

Or as I'd like to call it: THICC effect clouds can be used to soft-lock clients and/or permanently destroy your server's world! (if you don't know how to fix it)

Here is how it works:
1. Create a new world with commands enabled
2. Type the command:

/summon minecraft:area_effect_cloud ~ ~ ~ {Radius: 2.14748365e9}

3. ???

4. Minecraft client freezes, and only be fixed by a force stop with task manager

In singleplayer the effect cloud is deleted when restarting, as there is no way to save changes to the world (though if you did, that world would become unusable).

Servers do not crash, so using the above command will effectively render the immediate chunks on the server unusable until the effect entity can be removed via commands. And clients who come within render distance of the entity will freeze and crash.

Attachments

Comments 5

This issue first appeared on our creative mode server in 1.16.1, and persisted when we updated to 1.16.3.

Can confirm in 21w03a.

Can confirm in 21w06a.

Can confirm in 1.16.5 and 21w07a.

Can confirm in 21w08b. Video attached.

Sollace

Erik Broes

Community Consensus

Very Important

Commands, Crash

1.16.3, 21w03a, 1.16.5, 21w06a, 21w07a, 21w08b

21w11a

Retrieved