GHSA-7wrv-6h42-w54f is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in pocketmine/pocketmine-mp. A fix is available for pocketmine/pocketmine-mp — see the affected versions and patch details below.
PocketMine-MP vulnerable to server crash using badly formatted sign NBT in BlockActorDataPacket
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-7wrv-6h42-w54f plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 4.22.3composer require pocketmine/pocketmine-mp:^4.22.3 |
| 🐘Packagist | pocketmine/pocketmine-mp | ≥ 5.0.0&&< 5.2.1 | 5.2.1composer require pocketmine/pocketmine-mp:^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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-7wrv-6h42-w54f can be triaged on real exposure rather than presence alone.
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 Security finds GHSA-7wrv-6h42-w54f across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.