CVE-2026-86200 PocketMine-MP before 5.42.1 LogDoS via LoginPacket clientData JWT
Remote attackers can cause denial of service in PocketMine-MP by flooding server logs with junk data via malicious login packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-86200?
CVE-2026-86200 is a medium-severity denial of service vulnerability in pmmp PocketMine-MP, published on 9 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-779
Which versions are affected by CVE-2026-86200?
2 open source packages ship an affected version, including pocketmine/pocketmine-mp.
| Package | Affected | Fixed in |
|---|---|---|
pocketmine/pocketmine-mp Packagist | All versions | 5.42.1 |
pocketmine/pocketmine-mp Packagist | All versions | 5.42.1 |
How do I fix CVE-2026-86200?
Upgrade pocketmine/pocketmine-mp to 5.42.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-86200 being exploited?
There is no known exploitation of CVE-2026-86200 in the wild and no public exploit code.
Sources
Also known as GHSA-h5mw-4vcp-gq3w, GHSA-xp4f-g2cm-rhg7.