PocketMine MP vulnerable to uncontrolled resource consumption via mismatched type of 'InventoryTransactionPacket'

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 A "mismatch" type InventoryTransactionPacket is sent by the client to request a resync of all currently open inventories. Since PocketMine-MP does not rate-limit these "mismatch" transactions, and the syncing of inventories is not deferred until, e.g. the end of the current tick, they can be used as a very cheap bandwidth multiplier by making the server send out many MB of data (network serialized inventory items can be very large, especially when dealing with large amounts of NBT). This is not currently known to have been exploited in the wild. Patches This problem was fixed in 4.18.0-ALPHA2 by ca6d51498f12427a947467da8fcad7811418e6cc alongside the introduction of the ItemStackRequest system implementation. Workarounds Plugins can handle DataPacketReceiveEvent for InventoryTransactionPacket and check if the type is MismatchTransactionData. If it is, apply some kind of rate limit (e.g. max 1 per tick).

Published by the source

1 Jun 2023, 19:10 UTC

Last modified by the source

1 Jun 2023, 19:10 UTC

Source last checked

26 Oct 2026, 14:05 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-42qm-8v8m-m78c

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# Patch Next advisory brief: GHSA-42qm-8v8m-m78c

Advisory: PocketMine MP vulnerable to uncontrolled resource consumption via mismatched type of 'InventoryTransactionPacket'
IDs: GHSA-42qm-8v8m-m78c
Record: https://patchnext.com/advisories/ghsa-42qm-8v8m-m78c (revision 1, source checked 26 Oct 2026, 14:05 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 4.18.0-ALPHA2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist pocketmine/pocketmine-mp: affected < 4.18.0-ALPHA2; fixed in 4.18.0-ALPHA2

## 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-42qm-8v8m-m78c (GitHub-reviewed advisory GHSA-42qm-8v8m-m78c lists affected ranges: Packagist pocketmine/pocketmine-mp >=0 <4.18.0-ALPHA2)

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