Summary
Insufficient type validation in pocketmine/pocketmine-mp
Workarounds
It's non-trivial to workaround this, but can be done by handling InventoryTransactionPacket and PlayerAuthInputPacket to scrub inbound transaction data of bogus NBT that would cause these crashes.
For more information
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Impact
When an inventory interaction is performed (e.g. moving an item around an inventory), the client sends a serialized version of the itemstack to the server, which the server then deserializes and compares against its own copy. If the copies don't match, the transaction is invalid.
This involves deserializing item NBT from the client, which allows for bogus data to be provided. Usually, this is harmless, but in this particular case, it could result in crashes on certain types of bad data (e.g. incorrect ListTag type provided for the CanDestroy tag).
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
GHSA-G5RR-P69H-7V3G 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 (4.2.9); 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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This is fixed in 4.2.9 by commit 5a98b08ee8dc8ff14862cd83d2e4af9d212fefc2.
Frequently Asked Questions
- What is GHSA-G5RR-P69H-7V3G? GHSA-G5RR-P69H-7V3G is a high-severity improper input validation vulnerability in pocketmine/pocketmine-mp (composer), affecting versions < 4.2.9. It is fixed in 4.2.9. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is GHSA-G5RR-P69H-7V3G? GHSA-G5RR-P69H-7V3G 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-G5RR-P69H-7V3G? pocketmine/pocketmine-mp (composer) versions < 4.2.9 is affected.
- Is there a fix for GHSA-G5RR-P69H-7V3G? Yes. GHSA-G5RR-P69H-7V3G is fixed in 4.2.9. Upgrade to this version or later.
- Is GHSA-G5RR-P69H-7V3G exploitable, and should I be worried? Whether GHSA-G5RR-P69H-7V3G 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-G5RR-P69H-7V3G 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-G5RR-P69H-7V3G? Upgrade
pocketmine/pocketmine-mpto 4.2.9 or later.