CVE-2022-51011 in PocketMine-MP
Summary
by MITRE • 09/07/2026
PocketMine-MP before 4.2.10 fails to validate the total length of incoming chat message blobs before splitting them by newline characters, allowing attackers to send large messages containing many newlines. Malicious clients can send megabyte-sized chat packets and bombard the server with thousands of such messages, causing server lockups lasting seconds or minutes.
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Analysis
by VulDB Data Team • 09/07/2026
The vulnerability identified in PocketMine-MP versions prior to 4.2.10 represents a critical resource exhaustion flaw rooted in improper input validation within the network protocol handling subsystem. Specifically, the application fails to enforce an upper bound on the total byte length of incoming chat message blobs before processing them for newline delimiters. This architectural oversight allows clients to transmit significantly oversized data packets that exceed reasonable operational limits without triggering immediate rejection or truncation mechanisms. The absence of a pre-processing size check means the server accepts these malformed inputs and proceeds directly into memory allocation and string manipulation routines, which are not optimized to handle such extreme volumes of data efficiently.
From a technical perspective, the core issue lies in the sequence of operations performed on incoming network packets. When a chat message is received, the system attempts to split the payload by newline characters to process individual lines or segments. Because there is no preliminary validation of the total packet size, attackers can craft malicious payloads consisting of megabyte-sized blobs filled with numerous newline characters. This forces the server's memory manager and string processing libraries to allocate substantial amounts of contiguous memory and perform extensive iterative operations to parse the delimiters. The computational complexity associated with splitting such large strings is high, leading to significant CPU overhead and memory pressure that scales linearly or worse with packet size.
The operational impact of this vulnerability is severe, manifesting primarily as a Denial of Service condition against the game server infrastructure. By bombarding the server with thousands of these oversized chat packets in rapid succession, an attacker can induce prolonged server lockups lasting from several seconds to multiple minutes. During these periods, the server becomes unresponsive to legitimate player interactions, effectively halting gameplay and degrading service availability for all connected users. This type of attack exploits the asymmetry between the low cost of generating large network packets on the client side and the high computational cost required by the server to process them, a classic characteristic of resource exhaustion attacks.
This vulnerability aligns with CWE-787: Out-of-bounds Read in terms of memory access patterns during processing, but more accurately maps to CWE-400: Uncontrolled Resource Consumption due to the excessive allocation and usage of system resources such as CPU cycles and RAM. In the context of the MITRE ATT&CK framework, this behavior is consistent with techniques found under T1498: Network Denial of Service, specifically where an attacker leverages protocol-level inefficiencies or lack of rate limiting to disrupt service availability. The attack vector involves remote network communication using standard chat protocols, requiring no authentication if anonymous messaging is enabled, thereby increasing the potential blast radius and ease of exploitation for malicious actors.
To mitigate this vulnerability, it is imperative that developers implement strict input validation mechanisms at the earliest possible stage of packet processing. This includes enforcing a maximum allowable size limit for incoming chat messages before any parsing or splitting operations are initiated. Additionally, implementing rate limiting on message frequency can help prevent rapid-fire bombardment attacks even if individual packets are within acceptable size limits. Upgrading to version 4.2.10 or later is the primary remediation step as it addresses these validation gaps. Furthermore, deploying network-level firewalls or intrusion prevention systems that inspect packet sizes and drop oversized payloads before they reach the application layer can provide an additional defense-in-depth measure against such resource exhaustion attempts.