GHSA-7wrv-6h42-w54f
HIGHPocketMine-MP vulnerable to server crash using badly formatted sign NBT in BlockActorDataPacket
Blast Radius
pocketmine/pocketmine-mp🐘pocketmine/pocketmine-mpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A player sending a packet can cause the server to crash by providing incorrect sign data in NBT in BlockActorDataPacket.
Details
This vulnerability was discovered using the BlockActorDataPacket, but other packets may also be affected. The player would seem to just need to send an NBT with an incorrect type to throw this error.
[Server thread/CRITICAL]: pocketmine\nbt\UnexpectedTagTypeException: "Expected a tag of type pocketmine\nbt\tag\CompoundTag, got pocketmine\nbt\tag\ByteTag" (EXCEPTION) in "pmsrc/vendor/pocketmine/nbt/src/tag/CompoundTag" at line 107
--- Stack trace ---
#0 pmsrc/src/network/mcpe/handler/InGamePacketHandler(751): pocketmine\nbt\tag\CompoundTag->getCompoundTag(string[9] FrontText)
#1 pmsrc/vendor/pocketmine/bedrock-protocol/src/BlockActorDataPacket(50): pocketmine\network\mcpe\handler\InGamePacketHandler->handleBlockActorData(object pocketmine\network\mcpe\protocol\BlockActorDataPacket#220241)
#2 pmsrc/src/network/mcpe/NetworkSession(433): pocketmine\network\mcpe\protocol\BlockActorDataPacket->handle(object pocketmine\network\mcpe\handler\InGamePacketHandler#190572)
PoC
Use a bot or proxy to send a packet when editing a sign. This packet should contain an NBT with incorrect types but correct architecture.
Impact
This makes it possible to shutdown a server for someone who knows how to operate it. As this was discovered in 4.22.1, everyone with at least this version is affected.
Patches
This bug was fixed by 0c250a2ef09627b48aa52302f6cc7e1f2afb70ea in the 4.22.3 and 5.2.1 releases.
Workarounds
A plugin may be able to handle DataPacketReceiveEvent for BlockActorDataPacket, and verify that the FrontText tag is a TAG_Compound.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pocketmine/pocketmine-mp | ≥ 4.20.0&&< 4.22.3 | 4.22.3 |
| 🐘Packagist | pocketmine/pocketmine-mp | ≥ 5.0.0&&< 5.2.1 | 5.2.1 |
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 4.22.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7wrv-6h42-w54f 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-7wrv-6h42-w54f 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-7wrv-6h42-w54f. 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-7wrv-6h42-w54f in your dependencies?
O3 detects GHSA-7wrv-6h42-w54f across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.