CVE-2026-86204Public exploitNetwork attack vector

Authenticated server hang via unbounded JSON decoding

Published Sep 9, 2026 · Updated Sep 9, 2026

Denial of service in PMMP PocketMine-MP before 5.39.2 allows remote authenticated users to hang the server via oversized form responses. ModalFormResponsePacket handling decodes formData as JSON without a meaningful size limit and parses even nonexistent form IDs, consuming memory and CPU. A regular player must complete a session and spawn in the world; crafted arrays with millions of elements can freeze the server and delay all connections.

CVSS severity7.1
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in PMMP PocketMine-MP before 5.39.2 allows remote authenticated users to hang the server via oversized form responses. ModalFormResponsePacket handling decodes formData as JSON without a meaningful size limit and parses even nonexistent form IDs, consuming memory and CPU. A regular player must complete a session and spawn in the world; crafted arrays with millions of elements can freeze the server and delay all connections.

The record

CVE
CVE-2026-86204
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
PMMP
Product
PocketMine-MP
Classifications
CWE-770, T1499.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.39.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PMMP · PocketMine-MPversion=0 <5.39.2

Published CVSS scores

7.1PMMPCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.002Service Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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