GHSA-h6j3-j35f-v2x7
HIGHPocketMine-MP server crash with certain invalid JSON payloads in `LoginPacket` due to dependency vulnerability (3rd time)
Blast Radius
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Description
Impact
An attacker could crash PocketMine-MP by sending malformed JSON in LoginPacket.
netresearch/jsonmapper allows objects to be hydrated from scalar types in JSON. However, due to the lack of validation in the code for this feature, it may output improperly initialized objects if applied to objects whose constructors don't handle the input values.
Code handling these objects in PocketMine-MP could then crash due to @required properties not being set within the objects.
In addition, because JsonMapper does not respect bStrictObjectTypes when processing arrays, it's not possible to avoid the issue by disabling the feature.
Due to the relatively high number of security issues arising from unexpected behaviour in JsonMapper, the team is exploring options to replace it.
Patches
In the meantime, the issue was fixed by pmmp/netresearch-jsonmapper@b96a209f9e8b76b899a0d0918493cd87eb3c02a7 and 6872661fd03649cc7a8762c41c16e9ee5a4de1c9.
Workarounds
Detecting the malicious data that triggers this issue is of rather high difficulty, so it's not likely that a plugin would be able to easily remediate this.
References
https://github.com/cweiske/jsonmapper/pull/225 https://github.com/cweiske/jsonmapper/issues/226
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pocketmine/pocketmine-mp | all versions | 5.11.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pocketmine/pocketmine-mp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pocketmine/pocketmine-mp to 5.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h6j3-j35f-v2x7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-h6j3-j35f-v2x7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-h6j3-j35f-v2x7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-h6j3-j35f-v2x7 in your dependencies?
O3 detects GHSA-h6j3-j35f-v2x7 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.