Summary
Unchecked validity of Facing values in PlayerActionPacket
Workarounds
Using a plugin, cancel DataPacketReceiveEvent if the packet is PlayerActionPacket and the facing is outside the range 0-5 when receiving START_BREAK or CRACK_BLOCK actions, or UseItemTransactionData. However, beware that negative values may be legitimate in some cases.
For more information
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Impact
A remote attacker may crash a server by sending PlayerActionPacket with invalid facing values (e.g. negative), specifically with START_BREAK or CRACK_BLOCK actions, or with a UseItemTransactionData (typically in InventoryTransactionPacket).
GHSA-XH99-HW7H-WF63 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.0.6); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-XH99-HW7H-WF63? GHSA-XH99-HW7H-WF63 is a high-severity security vulnerability in pocketmine/pocketmine-mp (composer), affecting versions < 4.0.6. It is fixed in 4.0.6.
- How severe is GHSA-XH99-HW7H-WF63? GHSA-XH99-HW7H-WF63 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pocketmine/pocketmine-mp are affected by GHSA-XH99-HW7H-WF63? pocketmine/pocketmine-mp (composer) versions < 4.0.6 is affected.
- Is there a fix for GHSA-XH99-HW7H-WF63? Yes. GHSA-XH99-HW7H-WF63 is fixed in 4.0.6. Upgrade to this version or later.
- Is GHSA-XH99-HW7H-WF63 exploitable, and should I be worried? Whether GHSA-XH99-HW7H-WF63 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-XH99-HW7H-WF63 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-XH99-HW7H-WF63? Upgrade
pocketmine/pocketmine-mpto 4.0.6 or later.