Double items can be obtained by using the Class Cast Exception

[KaridaLee]

Description

https://youtu.be/PqD7u-UrpfQ
Here's the demo video. This vulnerability is 100% reproducible if done correctly. The server can even crash if there is an error in the operation. The main person responsible for this problem is MoJang, but the main material of the structure is provided by Create.

Game Log

https://mclo.gs/W2bRT0t

Debug Information

Client Info

Create:
	Mod Version: 0.5.1j
	Forge Version: 47.3.10
	Minecraft Version: 1.20.1

Graphics:
	Flywheel Version: 0.6.11-13
	Flywheel Backend: INSTANCING
	OpenGL Renderer: NVIDIA GeForce RTX 2060 SUPER/PCIe/SSE2
	OpenGL Version: 4.6.0 NVIDIA 565.90
	Graphics Mode: options.graphics.fancy

System Information:
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 17.0.2, Oracle Corporation
	JVM Flags: 11 total; -Xmx6481m -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32m -XX:-UseAdaptiveSizePolicy -XX:-OmitStackTraceInFastThrow -XX:-DontCompileHugeMethods -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
	Memory: 638617304 bytes (609 MiB) / 1979711488 bytes (1888 MiB) up to 6811549696 bytes (6496 MiB)
	Total Memory: 10731360256 bytes (10230 MiB) / 16952647680 bytes (16160 MiB)
	CPU: 11th Gen Intel(R) Core(TM) i5-11300H @ 3.10GHz @ 3.11 GHz; 4 cores / 8 threads on 1 socket(s)
	Graphics card #0: Intel(R) Iris(R) Xe Graphics (Intel Corporation (0x8086)); 1024.00 MB of VRAM
	Graphics card #1: NVIDIA GeForce RTX 2060 SUPER (NVIDIA (0x10de)); 4095.00 MB of VRAM
	Graphics card #2: NVIDIA GeForce MX450 (NVIDIA (0x10de)); 2048.00 MB of VRAM

Other Mods:

Server Info

Create:
	Mod Version: 0.5.1j
	Forge Version: 47.3.10
	Minecraft Version: 1.20.1

System Information:
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 17.0.2, Oracle Corporation
	JVM Flags: 11 total; -Xmx6481m -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32m -XX:-UseAdaptiveSizePolicy -XX:-OmitStackTraceInFastThrow -XX:-DontCompileHugeMethods -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
	Memory: 638617304 bytes (609 MiB) / 1979711488 bytes (1888 MiB) up to 6811549696 bytes (6496 MiB)
	Total Memory: 10731360256 bytes (10230 MiB) / 16952647680 bytes (16160 MiB)
	CPU: 11th Gen Intel(R) Core(TM) i5-11300H @ 3.10GHz @ 3.11 GHz; 4 cores / 8 threads on 1 socket(s)
	Graphics card #0: Intel(R) Iris(R) Xe Graphics (Intel Corporation (0x8086)); 1024.00 MB of VRAM
	Graphics card #1: NVIDIA GeForce RTX 2060 SUPER (NVIDIA (0x10de)); 4095.00 MB of VRAM
	Graphics card #2: NVIDIA GeForce MX450 (NVIDIA (0x10de)); 2048.00 MB of VRAM

Other Mods:

[VoidLeech]

Update supression via CCE is a vanilla bug that was fixed in 23w35a (a 1.20.2 snapshot). (not in the changelogs though)
See https://bugs.mojang.com/browse/MC-265132

[IThundxr]

Update supression via CCE is a vanilla bug that was fixed in 23w35a (a 1.20.2 snapshot). (not in the changelogs though) See https://bugs.mojang.com/browse/MC-265132

Create will still be patching it as the fix is simple and as can be seen by 23w35a mojang considers it a bug