PocketMine-MP versions >= 4.20.0 before 4.22.3 (and before 5.2.1 in the 5.x branch) fail to validate NBT tag types in BlockActorDataPacket. A player can crash the server by sending a packet containing sign NBT data with an incorrect tag type, triggering an unhandled UnexpectedTagTypeException that terminates the server process.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/pmmp/PocketMine-MP/commit/0c250a2ef09627b48aa52302f6cc7e1f2a…
disclosure@vulncheck.com
https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-7wrv-6h42-w54f
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/pocketmine-mp-before-4.22.3-denial-of-serv…
disclosure@vulncheck.com