CVE-2025-62782: Phoenix616 InventoryGui Item Duplication Vulnerability

CVE-2025-62782 Overview

CVE-2025-62782 affects InventoryGui, a Java library for creating chest-based graphical user interfaces (GUIs) in Bukkit and Spigot Minecraft server plugins. Versions 1.6.3-SNAPSHOT and earlier contain a business logic flaw in GuiStorageElement that permits item duplication when the server has the experimental Bundle item feature enabled. Attackers with a low-privileged authenticated account on a vulnerable server can exploit the interaction between Bundle items and storage GUIs to duplicate in-game items. The maintainer resolved the issue in version 1.6.4-SNAPSHOT.

Critical Impact
Authenticated players on affected Bukkit/Spigot servers running plugins that use InventoryGui GuiStorageElement with the experimental Bundle feature enabled can duplicate items, undermining server economies and integrity.

Affected Products

Phoenix616 InventoryGui versions 1.6.3-SNAPSHOT and earlier
Bukkit/Spigot plugins depending on vulnerable InventoryGui versions
Minecraft servers with the experimental Bundle item feature enabled

Discovery Timeline

2025-10-27 - CVE-2025-62782 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-62782

Vulnerability Analysis

InventoryGui provides an abstraction for chest-style inventory interfaces in Bukkit/Spigot plugins. The GuiStorageElement component wraps an underlying Inventory and mediates item placement and removal through click events. The vulnerability arises when players interact with the storage element using Bundle items, an experimental Minecraft feature that allows one item stack to contain multiple smaller stacks.

Because GuiStorageElement did not account for Bundle-specific click behavior, item transfers into and out of the storage inventory could be processed inconsistently. The result is that items placed inside a Bundle and then moved through the GUI can be duplicated rather than transferred. This is a business logic error mapped to CWE-837: Improper Enforcement of a Single, Unique Action.

Root Cause

The root cause is missing validation of ClickType and item type in the click handler of GuiStorageElement. Bundle items generate click events that the original handler did not recognize as special cases. As a result, the underlying inventory state and the GUI state diverge, producing duplicated ItemStack instances when the interaction completes.

Attack Vector

Exploitation requires an authenticated player on a server that (1) runs a plugin using a vulnerable version of InventoryGui with GuiStorageElement and (2) has the experimental Bundle item feature enabled. The attacker opens the plugin's storage GUI, uses Bundle interactions to trigger the mishandled click path, and retrieves duplicated items. No elevated privileges are needed beyond normal gameplay access, and user interaction is required.

java

// Security patch excerpt: src/main/java/de/themoep/inventorygui/GuiStorageElement.java
 import org.bukkit.ChatColor;
 import org.bukkit.Material;
 import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.ClickType;
 import org.bukkit.event.inventory.InventoryClickEvent;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.ItemStack;

// The fix imports ClickType so GuiStorageElement can identify
// Bundle-specific click events and block Bundle add/empty operations
// against storage elements, preventing duplication.

Source: GitHub commit 00e684b

Detection Methods for CVE-2025-62782

Indicators of Compromise

Sudden, unexplained growth of high-value item quantities in player inventories or economy plugins.
Server logs showing repeated interactions with plugin storage GUIs immediately followed by Bundle item usage.
Player transaction or shop plugin records where sold item volume exceeds legitimate acquisition rates.

Detection Strategies

Inventory the server's plugin dependencies and identify any that shade or depend on de.themoep:inventorygui at versions 1.6.3-SNAPSHOT or earlier.
Audit server.properties and feature-flag configuration for the experimental Bundle item feature and correlate with plugin usage.
Review economy and logging plugin data for statistical anomalies in item creation versus item destruction over time.

Monitoring Recommendations

Enable verbose logging on plugins that use InventoryGui storage elements to capture click events and item stack sizes.
Track player accounts that repeatedly open storage GUIs while holding Bundle items.
Alert on economy plugins reporting large or rapid balance changes tied to specific players.

How to Mitigate CVE-2025-62782

Immediate Actions Required

Upgrade InventoryGui to version 1.6.4-SNAPSHOT or later in all affected plugins and redeploy.
If upgrade is not immediately possible, disable the experimental Bundle item feature on the server.
Audit player inventories and economy balances for anomalies that predate the patch.

Patch Information

The fix is committed in Phoenix616/InventoryGui commit 00e684b and released in version 1.6.4-SNAPSHOT. The patch blocks Bundle add and empty operations inside GuiStorageElement by inspecting the ClickType of incoming InventoryClickEvent events. Full details are available in the GitHub Security Advisory GHSA-rgvh-4m82-fvjq and GitHub Issue #51.

Workarounds

Disable the experimental Bundle item feature until all plugins are updated to InventoryGui 1.6.4-SNAPSHOT or later.
Restrict access to plugins that expose GuiStorageElement GUIs using permission nodes until patching is complete.
Roll back duplicated items via administrative tooling where anomalies are confirmed.

bash

# Example Maven dependency pinning the fixed version
# pom.xml
# <dependency>
#   <groupId>de.themoep</groupId>
#   <artifactId>inventorygui</artifactId>
#   <version>1.6.4-SNAPSHOT</version>
# </dependency>

mvn clean package -U