CVE-2023-54392: PocketMine-MP before 4.22.3 Denial of Service via BlockActorDataPacket

Published Sep 9, 2026
·
Updated

PocketMine-MP versions >= 4.20.0 before 4.22.3 (and before 5.2.1 in the 5.x branch) fail to validate NBT tag types in BlockActorDataPacket. A player can crash the server by sending a packet containing sign NBT data with an incorrect tag type, triggering an unhandled UnexpectedTagTypeException that terminates the server process.

Affected Software

2 affected components
PocketMine PocketMine-MP>=4.20.0<4.22.3
PocketMine PocketMine-MP<5.2.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade PocketMine-MP to a version that resolves this vulnerability.

    Fixed in 4.22.3
  2. Upgrade

    Upgrade PocketMine-MP to a version that resolves this vulnerability.

    Fixed in 5.2.1

Event History

Sep 9, 2026
CVE Published
via MITRE·01:31 PM
Data Sourced
via MITRE·01:31 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Which deployments are affected?

PocketMine-MP 4.x deployments from 4.20.0 up to, but not including, 4.22.3 are affected. In the 5.x branch, versions before 5.2.1 are affected.

2

What access does an attacker need to crash a server?

An attacker needs player-level access sufficient to send a crafted BlockActorDataPacket. No user interaction is required after the malicious packet is sent.

3

What happens when the issue is exploited?

A crafted packet containing sign NBT data with an incorrect tag type triggers an unhandled UnexpectedTagTypeException. This terminates the server process, causing a denial of service.

4

How can administrators determine whether they are vulnerable?

Check the running PocketMine-MP version. Versions in the affected 4.x range below 4.22.3, or 5.x versions below 5.2.1, should be treated as vulnerable.

Contact

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