Is CVE-2026-86201 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-86201 being exploited in the wild.

How severe is CVE-2026-86201?

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=0,fixed=5.41.1.

Is there a fix for CVE-2026-86201?

Yes. pocketmine/pocketmine-mp (Packagist): upgrade to 5.41.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-86201 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-86201?

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.

CVE-2026-86201: PocketMine-MP denial of service in LoginPacket processing

CVE-2026-86201 · Severity: high · CVSS 7.5 · Published 2026-09-09

PocketMine-MP is a Minecraft server software that handles player login requests. A vulnerability in its login packet processing allows attackers to send specially crafted login packets with deeply nested or extremely large data structures, causing the server to consume excessive memory and CPU resources, which can crash the server entirely.

Technologies: pocketmine/pocketmine-mp (Packagist). Vendors: Packagist.

Quick answers

Is CVE-2026-86201 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-86201 being exploited in the wild.
How severe is CVE-2026-86201?: 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=0,fixed=5.41.1.
Is there a fix for CVE-2026-86201?: Yes. pocketmine/pocketmine-mp (Packagist): upgrade to 5.41.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-86201 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-86201?: 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 5.41.1 or later
```
composer require pocketmine/pocketmine-mp:^5.41.1
```

Technical details

The vulnerability is a denial-of-service (DoS) issue in the LoginPacketHandler component due to improper handling of unknown properties in the clientData JWT body. When the JsonMapper processes unexpected properties in the JWT, it logs the property value without length limitations or sanitization using var_export(), which can serialize massive or deeply nested object structures. An unauthenticated, network-reachable attacker can send a malicious LoginPacket with large/complex data in an unknown clientData property, triggering out-of-memory conditions and crashing the server. The vulnerability was fixed in version 5.41.1 by removing the var_export call and limiting logged property names to 80 characters. This affects PocketMine-MP versions before 5.41.1.

Affected products

PocketMine PocketMine-MP before 5.41.1

Identifiers

CVE-2026-86201
GHSA-h6rj-3m53-887h

Timeline

2026-04-04: disclosed
2026-09-09: patched: Version 5.41.1 released

References

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