Improperly checked IDs on itemstacks received from the client leading to server crash in PocketMine-MP

Exploitation

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

CVSS

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact Due to a workaround for unmapped network items implemented in 4.0.0-BETA5 (8ac16345a3bc099b62c1f5cfbf3b736e621c3f76), arbitrary item IDs are able to be written into an item's NBT. The intended purpose of this is to make said unmapped network items able to be moved around the inventory without issues. This led to an exploit due to internal limits on the range that item IDs can occupy (-32768 - 32767), while the tag type used to represent the replacement IDs for unknown items is a TAGInt, allowing a range from -(2^31) - 2^31 - 1. This leads to an uncaught exception which crashes the server. Patches 5fd685e07d61ef670584ed11a52fd5f4b99a81a7 Workarounds In theory this can be checked by plugins using a custom TypeConverter, but this is likely to be very cumbersome. For more information If you have any questions or comments about this advisory: Email us at team@pmmp.io

Published by the source

7 Jun 2022, 21:07 UTC

Last modified by the source

26 Dec 2025, 17:28 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fqx3-r75h-vc89

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# Patch Next advisory brief: GHSA-fqx3-r75h-vc89

Advisory: Improperly checked IDs on itemstacks received from the client leading to server crash in PocketMine-MP
IDs: GHSA-fqx3-r75h-vc89
Record: https://patchnext.com/advisories/ghsa-fqx3-r75h-vc89 (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: High (CVSS 7.5)
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 4.4.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist pocketmine/pocketmine-mp: affected >= 4.0.0-BETA5, < 4.4.2; fixed in 4.4.2

## 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-fqx3-r75h-vc89 (GitHub-reviewed advisory GHSA-fqx3-r75h-vc89 lists affected ranges: Packagist pocketmine/pocketmine-mp >=4.0.0-BETA5 <4.4.2)

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