Impact "LoginPacket" uses "BinaryStream->getLInt()" to read the lengths of JSON payloads it wants to decode. Unfortunately, "BinaryStream->getLInt()" returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causing "BinaryStream->get()" to throw an exception. In the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited. Patches e3fce7632b94e83fd6a518a87dcaf6a11681c4ac Workarounds This can be worked around by registering a custom "LoginPacket" implementation into "PacketPool" which overrides "this code" (https://github.com/pmmp/BedrockProtocol/blob/47532c95ea37d5f0365b23f734d70d943ff95295/src/LoginPacket.php#L54) to patch it. For more information * Email us at "team@pmmp.io" (mailto:team@pmmp.io)