How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

413,830

Total vulnerabilities in the database

PocketMine-MP: LogDoS by large complex unknown property logging in clientData in LoginPacket — pocketmine / pocketmine-mp

Uncontrolled Resource Consumption

Impact

Attackers can put large and/or complex structures as a value to an unknown property in the clientData JWT body in the Minecraft LoginPacket, causing the server to generate very long log messages. Additionally, the property name is logged without any length limitations or sanitization, which can also be abused for LogDoS.

This may be used to spam the log/console, waste CPU time serializing the offending structure, and potentially to crash the server entirely.

This happens because the JsonMapper instance used to process the JWT body is configured to warn on unexpected properties instead of rejecting them outright. While this behaviour increases flexibility for random changes introduced by Microsoft, it also creates vulnerabilities if not handled carefully.

This vulnerability affects PocketMine-MP servers exposed to a public network where unknown actors may have access.

PoC

Connect to the server using a custom client.
Send a Minecraft LoginPacket containing an unexpected JSON property (e.g., invalid_key) within the ClientData.
Set the value of invalid_key to a highly recursive or massive object structure (e.g., an array containing millions of elements or deeply nested arrays).
The server hits the warnUndefinedJsonPropertyHandler, which attempts to var_export the malicious object, leading to an Out-of-Memory crash.

A := make([]interface{}, 1)
	ptr := &amp;A
	for i := 0; i &lt; 500; i++ {
		next := make([]interface{}, 1000)
		(*ptr)[0] = next
		ptr = &amp;next
	}
	data := make([]int, 2000000)
	for i := 0; i &lt; 100; i++ {
		data[i] = i
	}
	(*ptr)[0] = data
	d.PlayFabID = A

Patches

The issue was addressed in https://github.com/pmmp/PocketMine-MP/commit/87d1c0cea09d972fd4c2fafb84dac2ecab7649f0 by removing the relevant var_export and limiting the length of the logged property name to 80 characters.

Workarounds

Plugins can handle DataPacketReceiveEvent to capture LoginPacket, and pre-process the clientData JWT to ensure it doesn't have any unusual properties in it. This can be achieved using JsonMapper (see the original affected code below) and setting the bExceptionOnUndefinedProperty flag to true. A JsonMapper_Exception will be thrown if the JWT is problematic.

However, it's important to caveat that this approach may cause login failures if any unexpected properties appear out of the blue in future versions (which has happened in the past).

Published: Apr 6, 2026
Updated: Apr 7, 2026
GHSA: GHSA-h6rj-3m53-887h
Severity: High
Exploit:
CISA KEV:

CVSS v3:

Severity: High
Score: 7.5
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWEs:

CWE-400

Affected Software
References

Software	Affected versions
pocketmine / pocketmine-mp	`< 5.41.1`

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.