CVE-2026-86200VulnerabilityPublished 09/09/2026Updated 10/08/2026

CVE-2026-86200: Logging of Excessive Data in pmmp PocketMine-MP

Affects pmmp PocketMine-MPSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium · fixed in 5.42.1 : update pmmp PocketMine-MP when convenient.

Data as of 10/25/2026, 04:40:14 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

Exploitation: Not in CISA KEV, no exploitation reported
EPSS: 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.42.1

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

What to do

Affected software

Product	Affected	Fixed in
pmmpPocketMine-MP	Affected <5.42.1	Fixed in 5.42.1
GitHubpmmp/PocketMine-MP`pkg:github/pmmp/PocketMine-MP`Other threats	Affected <5.42.1	Fixed in 5.42.1

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AI-suggested

A fix is available in PocketMine-MP version 5.42.1. Users should upgrade to version 5.42.1 or later to remediate this vulnerability. No other mitigation guidance is provided or required.

Description

PocketMine-MP before version 5.42.1 has a denial of service vulnerability in its LoginPacket handler. Remote attackers can exploit this by sending login packets containing numerous junk properties in the clientData JWT, causing excessive logging and CPU usage. This can degrade server performance and potentially disrupt service availability.

Impact

Exploitation allows remote attackers to cause denial of service by flooding the server with excessive log messages and consuming CPU resources. This degrades server performance and may disrupt availability for legitimate users.

Summary

CVE-2026-86200 describes a denial of service vulnerability in PocketMine-MP versions prior to 5.42.1. The flaw exists in the LoginPacket handler, where attackers can inject many unknown properties into the clientData JWT. This triggers excessive warning message logging, wasting server CPU resources and degrading performance. The vulnerability is remotely exploitable without authentication or user interaction.

References

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