Playing too many sounds crashes / blue screens a client
A server operator can crash users computers by playing too many sounds, an easy way to do this is with command blocks.
Place down a command block, set it to "Repeat" and paste in the command
/playsound minecraft:music.credits master CLIENT_TO_CRASH ~ ~ ~ 10000000 1
now click "Done" and CTRL+Middle click to copy the command block with its NBT data, place about 256 (16x16, another layer could be added for a faster crash.) command blocks and put redstone above, now power them all at once and the client should crash and(or) there computer will freeze up, forcing them to power off there computer.
If the user closes there client fast enough then nothing will happen, but if they wait the whole client will freeze, any other programs running will stop responding and the only way to stop it will be to power off your computer with the power button.
Been testing this with friends on a vanilla server (1.15.2), it only works if they have sounds on. I also think this issue has something to do with RAM, as one of my friends had given minecraft 32 GB ram and had ~64 GB more ram unused, he didn't crash instantly, but took about 5-7 ish minutes, when he crashed he got a blue screen and was forced to restart, when he came back online he couldn't start minecraft anymore as it says something along the lines of "Couldn't detect graphic card" (This was fixed after some messing around with the NVIDIA panel).
I wanted to report this privately as this could be heavily abused on minecraft servers, and could lead to loss of unsaved work if done to the right person.