CVE-2026-86201

PocketMine-MP before 5.41.1 contains a denial of service vulnerability in LoginPacket processing where large or complex structures in unknown clientData JWT properties cause excessive logging without sanitization. Attackers can send crafted LoginPackets with deeply nested or massive object structures to trigger out-of-memory conditions and crash the server.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.6% chance of exploitation in the next 30 days; higher than 48% of CVEs (scores of 2026-10-25)

CWE

CWE-400

Published

2026-09-09

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

References

• https://github.com/pmmp/PocketMine-MP/commit/87d1c0cea09d972fd4c2fafb84dac2ecab7649f0
• https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-h6rj-3m53-887h
• https://www.vulncheck.com/advisories/pocketmine-mp-before-5.41.1-logdos-via-loginpacket-clientdata
• https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-h6rj-3m53-887h

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