PT-2026-88983 · Pmmp+2 · Pocketmine-Mp+1
CVSS v4.0
CVSS v3.1
7.1
High
| Vector | AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
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
btUnexpectedTagTypeException: "Expected a tag of type pocketmine
bttagCompoundTag, got pocketmine
bttagByteTag" (EXCEPTION) in "pmsrc/vendor/pocketmine/nbt/src/tag/CompoundTag" at line 107
--- Stack trace ---
#0 pmsrc/src/network/mcpe/handler/InGamePacketHandler(751): pocketmine
bttagCompoundTag->getCompoundTag(string[9] FrontText)
#1 pmsrc/vendor/pocketmine/bedrock-protocol/src/BlockActorDataPacket(50): pocketmine
etworkmcpehandlerInGamePacketHandler->handleBlockActorData(object pocketmine
etworkmcpeprotocolBlockActorDataPacket#220241)
#2 pmsrc/src/network/mcpe/NetworkSession(433): pocketmine
etworkmcpeprotocolBlockActorDataPacket->handle(object pocketmine
etworkmcpehandlerInGamePacketHandler#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.Exploit
Fix
RCE
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Weakness Enumeration
Related Identifiers
Affected Products
Pocketmine-Mp
Pocketmine/Pocketmine-Mp