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MC-253464

Random "lost connection" error not associated with a player: java.lang.IndexOutOfBoundsException: readerIndex + length exceeds writerIndex: PooledUnsafeDirectByteBuf

My server was left on and a random IP from France caused an error. The IP wasn't associated with a player name, and none of the guys that go on my server live anywhere near France... so I figured it might be some kind of exploit attempt or port scanning bot.

The attached log contains the error as well, but here it is for easy viewing:

[10:11:07] [Server thread/INFO]: /163.172.139.143:56026 lost connection: Internal Exception: io.netty.handler.codec.DecoderException: java.lang.IndexOutOfBoundsException: readerIndex(18) + length(1) exceeds writerIndex(18): PooledUnsafeDirectByteBuf(ridx: 18, widx: 18, cap: 18)

I tried googling for similar 'lost connection' errors, but I kept seeing unrelated stuff instead... so I decided I'd write my own bug report.

If this is not a vulnerable security risk, feel free to un-private this report so that the error can be searched by other users. It's not my IP nor the IP of anyone I know, so I don't care if it's censored or not.

Environment

Operating System: Pop!_OS 22.04 LTS
Architecture: 64-bit
GNOME Version: 42.1
Windowing System: X11
Memory: 16 GB
Processor: Intel Core i7-2600 CPU @ 3.40GHz x 8
Graphics: Mesa Intel HD Graphics 2000 (SNB GT1)
-------------------
java -version
openjdk version "17.0.3" 2022-04-19
OpenJDK Runtime Environment (build 17.0.3+7-Ubuntu-0ubuntu0.22.04.1)
OpenJDK 64-Bit Server VM (build 17.0.3+7-Ubuntu-0ubuntu0.22.04.1, mixed mode, sharing)

Linked issues

Attachments

Comments 2

Is the server using any mods or plugins? If so, you need to report this to the mod's developers.

The server had no mods. It was a completely vanilla 1.19 server jar.

I'm unsure if the 'relates to' issue is actually related, since there's no IndexOutOfBoundsException in REALMS-1656 and the sizes are wildly different. But maybe that's why they aren't considered 'duplicates' and just 'relates to'.

I'm also not sure if my issue was caused by a minecraft client attempting to access the server. I'm doubtful that it was a legitimate player login attempt.

ipyronic

(Unassigned)

Plausible

Networking

1.19

Retrieved