CVE-2026-86203

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.

PocketMine-MP versions before 5.39.2 contain a network amplification vulnerability in ActorEventPacket handling that allows clients to trigger consuming animations for all visible players. Attackers can send crafted ActorEventPacket messages to spam animation events to other clients and waste server CPU and memory resources.

PocketMine-MP before 5.41.1 contains a denial of service vulnerability in LoginPacket processing where large or complex structures in unknown clientData JWT properties cause excessive logging without sanitization. Attackers can send crafted LoginPackets with deeply nested or massive object structures to trigger out-of-memory conditions and crash the server.

PocketMine-MP versions before 5.42.1 contain a denial of service vulnerability in the LoginPacket handler that allows remote attackers to flood warning messages by injecting numerous junk properties into the clientData JWT. Attackers can craft malicious login packets with excessive unknown properties to waste server CPU time and degrade performance.

PocketMine-MP versions before 5.43.1 fail to properly validate the Certificate field during offline login authentication. Unauthenticated players can trigger an uninitialized property access error that crashes the server.

PocketMine-MP versions before 5.44.2 fail to properly validate multiple ResourcePackClientResponsePacket packets with STATUS_COMPLETED status during resource pack handling. Malicious clients can send batches of these packets to repeatedly trigger pre-spawn progression, creating duplicate Player objects and amplifying memory consumption and network traffic.

PocketMine-MP versions before 5.25.2 fail to limit the explode() function in packet parsing, allowing malicious clients to waste server resources. Attackers can send crafted packets with excessive delimiters to consume CPU and memory through sign editing, JWT parsing, and command parsing endpoints.

PocketMine-MP before 5.32.1 fails to validate uniqueness of pack UUIDs in ResourcePackClientResponsePacket STATUS_SEND_PACKS handling, allowing authenticated clients to trigger duplicate pack transmissions. Attackers can send multiple copies of valid pack UUIDs in a single packet to exhaust server memory and cause denial of service.

PocketMine-MP before 5.11.1 contains a denial of service vulnerability in LoginPacket JSON processing that allows remote attackers to crash the server by sending malformed JSON data. Attackers can exploit improper object initialization from scalar JSON types to trigger unset required properties, causing the application to crash.

PocketMine-MP before version 5.11.2 contains a denial of service vulnerability in BookEditPacket handling that crashes the server when an invalid inventory slot value is provided. Attackers can send a crafted BookEditPacket with an inventory slot greater than 35 to trigger an unhandled exception and crash the server.