CVE-2025-62784 affects the InventoryGui library developed by Phoenix616, which is widely used to create chest graphical user interfaces (GUIs) for Bukkit/Spigot Minecraft server plugins. The vulnerability arises from improper enforcement of a single, unique action (CWE-837) within the GuiStorageElement component. Specifically, when the experimental Bundle item feature is enabled on the server, any plugin using a GUI that allows item extraction from GuiStorageElement can be exploited to duplicate items. This occurs because the library fails to properly restrict multiple identical actions that should be unique, enabling attackers with low privileges to bypass intended constraints and create duplicate items. The vulnerability does not require user interaction and can be exploited remotely over the network without authentication, increasing its risk profile. The CVSS 4.0 base score is 5.3 (medium), reflecting its moderate impact on integrity and low impact on confidentiality and availability. The vulnerability was publicly disclosed on October 27, 2025, and fixed in InventoryGui version 1.6.5. No public exploits have been observed, but the potential for abuse in multiplayer Minecraft servers is significant, as item duplication can undermine server economies, disrupt gameplay balance, and facilitate cheating or fraud.

For European organizations operating Minecraft servers, especially those hosting multiplayer environments or commercial servers, this vulnerability poses a risk to game integrity and user trust. Item duplication can lead to economic imbalances within the game, devaluing legitimate player achievements and potentially causing financial losses if in-game items have real-world value. Servers used for educational, entertainment, or commercial purposes may suffer reputational damage and user attrition. Additionally, duplicated items could be leveraged to bypass gameplay restrictions or enable further exploits. While the vulnerability does not directly compromise server confidentiality or availability, the integrity impact is significant in the context of game mechanics and community fairness. The medium severity rating reflects these factors. European organizations with large Minecraft player bases or those providing hosting services should prioritize remediation to maintain service quality and compliance with fair play policies.

The primary mitigation is to upgrade the InventoryGui library to version 1.6.5 or later, where the vulnerability is fixed. Server administrators should audit their plugins to identify any that use InventoryGui and verify the version in use. If upgrading immediately is not feasible, temporarily disabling the experimental Bundle item feature can prevent exploitation. Additionally, server operators should monitor for unusual item duplication activity and implement logging to detect potential abuse. Applying strict access controls to server management interfaces and limiting plugin installation to trusted sources reduces the risk of exploitation. Regular backups of server data can help recover from any adverse effects caused by exploitation. Finally, educating server administrators and plugin developers about this vulnerability and encouraging timely patching is critical to reduce exposure.