# CVE-2023-54390: PocketMine-MP denial of service in LoginPacket JSON parsing

Source: https://junglewise.ai/threats/cve-2023-54390-pocketmine-mp-denial-of-service-in-loginpacket-json-parsing  
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-2023-54390 · Severity: high · CVSS 7.5 · Published 2026-09-09

PocketMine-MP is a popular PHP-based Minecraft server software. The vulnerability allows unauthenticated attackers to crash the server by sending malformed JSON packets during the login phase, causing a denial of service. Server administrators will experience unexpected downtime and service unavailability.

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-2023-54390 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2023-54390 being exploited in the wild.

**How severe is CVE-2023-54390?** High severity, with a CVSS score of 7.5, published 9 September 2026.

**Which products and versions are affected?** pocketmine/pocketmine-mp (Packagist) ECOSYSTEM:introduced=5.0.0,fixed=5.3.1.

**Is there a fix for CVE-2023-54390?** Yes. pocketmine/pocketmine-mp (Packagist): upgrade to 5.3.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2023-54390 attacked?** It is attacked over the network.

**Am I affected by CVE-2023-54390?** 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 5.3.1 or later

  ```sh
  composer require pocketmine/pocketmine-mp:^5.3.1
  ```


## Technical details

The vulnerability is a denial of service caused by improper null value handling in the JsonMapper library used to parse LoginPacket JSON data. When a malformed LoginPacket containing unexpected NULL elements in JSON arrays is received, the JsonMapper library (due to its bStrictNullTypes validation bypass) allows NULL values in arrays that don't expect them, causing downstream code to crash. The vulnerability requires no authentication or user interaction and is reachable over the network from any unauthenticated client. Attackers can repeatedly send malformed packets to repeatedly crash the server. PocketMine-MP versions before 5.3.1 and 4.23.0 are affected; patches were released that update the bundled JsonMapper library to include proper validation.

## Affected products

- PocketMine-MP PocketMine-MP before 5.3.1 and before 4.23.1

## Identifiers

- CVE-2023-54390
- GHSA-92jh-gwch-jq38

## Timeline

- 2023-09-13: disclosed
- 2023-09-13: patched: Patched in versions 5.3.1 and 4.23.1

## References

- [https://github.com/pmmp/PocketMine-MP/commit/4f90e8dab1c9df331fad7d3d89823404e882668c](https://github.com/pmmp/PocketMine-MP/commit/4f90e8dab1c9df331fad7d3d89823404e882668c)
- [https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-92jh-gwch-jq38](https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-92jh-gwch-jq38)

## 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 item duplication via despawn entity attack race condition](https://junglewise.ai/threats/cve-2026-86203-pocketmine-mp-item-duplication-via-despawn-entity-attack-race)
- [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)