🛡️ GHSA-gj94-v4p9-w672 — pocketmine-mp

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Denial-of-service vulnerability processing large chat messages containing many newlines

Impact

PocketMine-MP caps maximum chat message length at 512 Unicode characters, or about 2048 bytes. No more than 2 chat messages may be sent per tick. However, due to legacy reasons, incoming chat message blobs are split by \n, and each part is treated as a separate message, the length of each part is individually checked. The length of the whole message is not checked.

This leads to an exploitable performance issue, in which a malicious client may send a chat packet of several megabytes containing nothing but \n newline characters. The server will parse this into a very large array and spend a long time (several milliseconds) iterating over it for no reason.

Furthermore, due to the lack of sufficient rate limit checks before parsing messages, malicious clients may bombard the server with many thousands of these malicious messages, causing lockups for a significant amount of time (seconds or minutes).

Patches

This bug was addressed in https://github.com/pmmp/PocketMine-MP/commit/df33e179e5d3ff13b56a2d7060bf592b0f797258 by:

  • checking the length of the incoming message as a whole before parsing it - it may not be larger than messageCounter * maxChatMessageSize (messageCounter is decremented once for every message sent)
  • limiting the maximum number of times a message may be split on newlines before giving up and discarding the message (maximum 3 parts; anything after the first 2 parts is discarded)

Workarounds

Handle DataPacketReceiveEvent and check for these excessive newlines in incoming TextPacket.

For more information

If you have any questions or comments about this advisory:

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability low.

Affected software

GHSA-gj94-v4p9-w672 is recorded against 1 package.

  • pocketmine/pocketmine-mp (fixed in 4.2.10)

Timeline and source

Published on 25 May 2022 and last revised on 26 December 2025. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Package)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2022-05-25
Updated 2026-08-20
Modified 2025-12-26
Fix URL N/A

Affected Packages

Software From version Fixed in
pocketmine/pocketmine-mp — 4.2.10

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