PocketMine-MP versions before 5.39.2 fail to limit JSON payload size in ModalFormResponsePacket handling, allowing authenticated players to cause denial of service. Attackers can send modal form response packets with massive JSON arrays to exhaust server memory and CPU resources, rendering the server unresponsive.
PocketMine-MP before 4.18.0-ALPHA2 fails to rate-limit mismatch type InventoryTransactionPacket requests, allowing attackers to trigger excessive inventory synchronization. Attackers can send numerous mismatch transactions to force the server to transmit large amounts of serialized inventory data, consuming significant bandwidth without authentication.
PocketMine-MP versions before 5.3.1 and 4.23.1 fail to validate that the identityPublicKey in LoginPacket uses the required secp384r1 elliptic curve. Attackers can provide LoginPackets with keys using different curves or non-EC key types to pass login verification but trigger an uncaught exception during ECDH key derivation, crashing the server.
PocketMine-MP 3.x (before 3.27.0) does not implement Minecraft Bedrock protocol encryption, so the server cannot verify that a connecting client possesses the private key corresponding to its login token. An attacker who captures a valid login from another player's session (for example by tricking the player into connecting to an attacker-controlled server) can replay that login to impersonate the victim and pass XBOX Live authentication until the JWT token expires (typically 2-3 days). This affects servers directly reachable over the internet that are not behind a proxy with encryption enabled. Fixed in 4.0.0 and backported to 3.27.0.
PocketMine-MP versions before 4.2.3 fail to validate damage metadata values in tool and armor item NBT data received from clients. Attackers can send negative or out-of-range damage values in itemstack NBT to trigger unhandled exceptions in the Durable class, causing server crashes.
PocketMine-MP before 4.12.3 fails to limit unauthenticated sessions, allowing attackers to exhaust player slots by creating sessions without sending LoginPacket. Attackers can flood the server with unauthenticated connections that occupy max-player slots, preventing legitimate players from joining.