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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

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…

Published by the source

25 May 2022, 22:34 UTC

Last modified by the source

26 Dec 2025, 17:29 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gj94-v4p9-w672

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# Patch Next advisory brief: GHSA-gj94-v4p9-w672

Advisory: Denial-of-service vulnerability processing large chat messages containing many newlines
IDs: GHSA-gj94-v4p9-w672
Record: https://patchnext.com/advisories/ghsa-gj94-v4p9-w672 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pocketmine/pocketmine-mp 4.2.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist pocketmine/pocketmine-mp: affected < 4.2.10; fixed in 4.2.10

## Suggested inspection (read-only)
- Packagist pocketmine/pocketmine-mp: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pocketmine/pocketmine-mp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gj94-v4p9-w672 (GitHub-reviewed advisory GHSA-gj94-v4p9-w672 lists affected ranges: Packagist pocketmine/pocketmine-mp >=0 <4.2.10)

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