CVE-2025-34124 in Heroes of Might and Magic III
Summary
by MITRE • 07/17/2025
A buffer overflow vulnerability exists in Heroes of Might and Magic III Complete 4.0.0.0, HD Mod 3.808 build 9, and Demo 1.0.0.0 via malicious .h3m map files that exploit object sprite name parsing logic. The vulnerability occurs during in-game map loading when a crafted object name causes a buffer overflow, potentially allowing arbitrary code execution. Exploitation requires the victim to open a malicious map file within the game.
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Analysis
by VulDB Data Team • 07/18/2025
This buffer overflow vulnerability in Heroes of Might and Magic III represents a critical security flaw that exploits the game's map loading mechanism through malformed object sprite names in .h3m files. The vulnerability specifically targets the parsing logic that handles object sprite names during map initialization, creating an opportunity for attackers to execute arbitrary code on affected systems. The flaw exists in multiple versions including the complete edition 4.0.0.0, HD Mod 3.808 build 9, and demo version 1.0.0.0, indicating a widespread impact across different game distributions. The technical implementation involves the game engine's insufficient bounds checking when processing object names that exceed allocated buffer sizes, allowing attackers to overwrite adjacent memory locations with malicious data. This type of vulnerability falls under the CWE-121 buffer overflow category, specifically classified as a stack-based buffer overflow where the excessive data overwrite corrupts the program's execution flow. The attack vector requires social engineering to convince victims to open malicious map files, making it a user-initiated exploit that leverages the game's legitimate map loading functionality as an attack surface. The operational impact extends beyond simple code execution to potentially allow full system compromise, as the vulnerability could be exploited to gain unauthorized access to player data, game saves, or even execute malicious payloads on the host system. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution, where the buffer overflow enables arbitrary code execution through the game's native execution environment. The exploitation process requires careful crafting of .h3m map files with oversized object sprite names that trigger the buffer overflow during the map loading sequence. Given that the game's map format is designed to store extensive game data including objects, terrain features, and player information, the buffer overflow can potentially corrupt critical game state variables, leading to unpredictable behavior or complete application crashes. The vulnerability demonstrates a classic memory safety issue where insufficient input validation allows attackers to manipulate program execution flow through carefully constructed malicious inputs. The affected versions suggest that this flaw has persisted across multiple releases, indicating inadequate security testing during the development lifecycle. Security researchers should note that this vulnerability represents a significant risk for online gaming communities where users may download maps from untrusted sources, as the attack can be initiated through legitimate game functionality. The lack of proper bounds checking in the sprite name parsing logic creates an exploitable condition that can be leveraged for privilege escalation or data theft. The vulnerability's impact is particularly concerning in multiplayer gaming environments where the attacker could potentially compromise other players' systems through malicious shared maps. Mitigation efforts should focus on immediate patching of affected versions, implementation of input validation controls, and awareness campaigns to educate users about the risks of opening untrusted map files. Additionally, game developers should implement robust memory safety mechanisms including stack canaries, address space layout randomization, and heap-based buffer overflow protections to prevent similar vulnerabilities from occurring in future releases. The vulnerability underscores the importance of security testing in gaming applications and the need for comprehensive input validation across all data parsing functions within game engines.