# CVE-2026-86203: PocketMine-MP item duplication via despawn entity attack race condition

Source: https://junglewise.ai/threats/cve-2026-86203-pocketmine-mp-item-duplication-via-despawn-entity-attack-race  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-09. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86203 · Severity: low · CVSS 3.7 · Published 2026-09-09

PocketMine-MP is a Minecraft server implementation used to host multiplayer game servers. A race condition allows an attacker to kill a player who is disconnecting and trigger multiple death events, causing inventory items and experience to drop multiple times, enabling item duplication. While the impact is limited to in-game items, this can undermine server economy and gameplay fairness on affected servers.

Technologies: [pocketmine/pocketmine-mp (Packagist)](https://junglewise.ai/threats/technologies/pocketmine-pocketmine-mp). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-86203 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86203 being exploited in the wild.

**How severe is CVE-2026-86203?** Low severity, with a CVSS score of 3.7, published 9 September 2026.

**Which products and versions are affected?** pocketmine/pocketmine-mp (Packagist) ECOSYSTEM:introduced=0,fixed=5.39.2.

**Is there a fix for CVE-2026-86203?** Yes. pocketmine/pocketmine-mp (Packagist): upgrade to 5.39.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86203 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-86203?** Check whether you run pocketmine/pocketmine-mp (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- pocketmine/pocketmine-mp (Packagist): upgrade to 5.39.2 or later

  ```sh
  composer require pocketmine/pocketmine-mp:^5.39.2
  ```


## Technical details

The vulnerability is a race condition in entity state validation (CWE-664: Improper Control of a Resource Through its Lifetime). When a player disconnects or dies, the entity is flagged for despawn but remains in the World entity table. If an attack packet from another client arrives during a narrow timing window, the handler calls World.getEntity() without checking the flagged-for-despawn state, allowing the death handler to execute multiple times. Attack vector is network-based (another player sends attack packets) with high complexity (precise timing required) and no authentication required. An attacker can duplicate items by timing an attack on a disconnecting victim. The vulnerability was patched in version 5.39.2.

## Affected products

- PocketMine PocketMine-MP before 5.39.2

## Identifiers

- CVE-2026-86203
- GHSA-f9jp-856v-8642

## Timeline

- 2026-04-04: disclosed
- 2026-05-09: patched: Fixed in version 5.39.2

## References

- [https://github.com/pmmp/PocketMine-MP/commit/c0719b76b18f2508143134e79bc9f1aa39109683](https://github.com/pmmp/PocketMine-MP/commit/c0719b76b18f2508143134e79bc9f1aa39109683)
- [https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-f9jp-856v-8642](https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-f9jp-856v-8642)

## Related threats

- [PocketMine-MP denial of service in ModalFormResponsePacket handling](https://junglewise.ai/threats/cve-2026-86204-pocketmine-mp-denial-of-service-in-modalformresponsepacket)
- [PocketMine-MP network amplification in ActorEventPacket](https://junglewise.ai/threats/cve-2026-86202-pocketmine-mp-network-amplification-in-actoreventpacket)
- [PocketMine-MP denial of service in LoginPacket processing](https://junglewise.ai/threats/cve-2026-86201-pocketmine-mp-denial-of-service-in-loginpacket-processing)
- [PocketMine-MP denial of service in LoginPacket handler](https://junglewise.ai/threats/cve-2026-86200-pocketmine-mp-denial-of-service-in-loginpacket-handler)
- [PocketMine-MP improper validation of ResourcePackClientResponsePacket](https://junglewise.ai/threats/cve-2026-86198-pocketmine-mp-improper-validation-of)