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DevilutionX EUVDEUVD-2026-110572

| CVE-2026-116841 MEDIUM
Out-of-bounds Read (CWE-125)
2026-10-27 VulnCheck GHSA-mqmm-g9r5-977r
6.8
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Place crafted .mpq in game data path
  2. Delivery
    Victim loads mod archive
  3. Exploit
    Unchecked block_table_index read past mpq_map
  4. Execution
    Out-of-bounds heap read
  5. Impact
    Game crashes (denial of service)

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the attacker to place a specially crafted .mpq archive (for example, bundled inside a DevilutionX mod) into the game's data path, and requires the victim to then load that archive by running the game - this is the UI:P/user-interaction and AV:L/local-access condition. The malicious block_table_index value is only reached through libmpq's hash/block table lookup (libmpq__file_number_from_hash), so a legitimate, unmodified installation using only official game data is not affected. Limiting factors: no remote or network path, no privilege escalation, and dependence on the user installing and loading an untrusted third-party archive; impact is limited to crashing the game process (availability), with no confidentiality or integrity effect per the vendor CVSS.

Impact

This is a genuinely medium-severity, low-urgency issue, and the signals are internally consistent rather than conflicting. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H) describes a local vulnerability whose only impact is to availability - the out-of-bounds read in libmpq__file_number_from_hash crashes the game; confidentiality impact is explicitly rated N, so despite the CWE-125 'out-of-bounds read' classification and the description's mention of reading heap memory, the vendor-scored realistic outcome is a denial-of-service (crash), not attacker-controlled data exfiltration. Exploitation is not remote: the attacker must get a crafted .mpq archive onto the victim's local data path (e.g., distributing a malicious mod) and the victim must load it (UI:P). EPSS is very low (0.12%, 2nd percentile), there is no CISA KEV listing, and the vuln.today decision label is 'this_month' (not act_now/emergency) - all of which agree this is a patch-on-normal-cadence issue rather than a fire drill. The one caveat defenders should note: PR:N is scored because no authentication is needed, but exploitation is entirely gated on social-engineering a user into installing an untrusted mod/archive, so real-world risk is bounded by user behavior, not by network exposure.

Exploit ScenarioDerived

An attacker publishes a malicious DevilutionX mod containing a crafted .mpq archive with an out-of-range block_table_index. A victim downloads and installs the mod into the game's data path and launches the game; when libmpq performs its hash/block table lookup it reads past the mpq_map allocation and the game crashes (denial of service). A public technical write-up describing the flaw exists, but exploitation requires local file placement and user interaction, so there is no remote network vector.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 28, 2026

An out-of-bounds read in the libmpq library bundled with DevilutionX 1.4.0 through 1.5.5 lets a crafted .mpq archive crash the game: the file-number lookup routine libmpq__file_number_from_hash uses an unchecked block_table_index from the archive's hash table to index the block table array, reading past the heap buffer (mpq_map) and terminating the process. The attack is not remote - the attacker must first get a malicious archive into the game's data path (for example distributed as a mod) and the victim must then launch DevilutionX and load it, so a legitimate install using only official Blizzard data is not affected. Per the assessed impact the consequence is availability only (crash), with no confidentiality or integrity effect; there is no CISA KEV listing, EPSS is low at 0.12% (2nd percentile), and no working public exploit code is confirmed, although a public technical write-up of the flaw exists.

RemediationAI

Patch status is vendor-provided: an upstream fix is available through DevilutionX pull request https://github.com/diasurgical/DevilutionX/pull/8482 (referenced as the patch in the CVE record), and the vendor advisory at https://www.vulncheck.com/advisories/devilutionx-1.4.0-through-1.5.5-out-of-bounds-read-via-libmpq-hash-table-lookup should be consulted for the release that carries it - the input data does not state an exact fixed version number, so confirm the shipping version in the advisory or release notes before upgrading from the 1.4.0-1.5.5 range. Because the fix is a bounds check on the block-table index, no configuration toggle removes the bug; the practical interim control is to load only .mpq archives obtained from trusted sources and to avoid installing or launching untrusted mods, which removes the attacker's delivery path at the cost of limiting mod usage in installations that rely on third-party content. Note that exploitation is local and requires the victim to open the crafted archive, impact observed is a game-process crash with no confidentiality or integrity loss, EPSS is 0.12% and there is no KEV entry, so this is a routine patch-cycle item (vendor priority 'this_month') rather than an emergency.

Affected VersionsENISA

DevilutionX 1.4.0 ≤1.5.5

Affected Packages

euvd devilutionx no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

MPQ (MoPaQ) is Blizzard's archive format used by Diablo and other titles; it stores file entries in a hash table whose entries carry a block_table_index pointing into a separate block table. DevilutionX vendors libmpq (3rdParty/libmpq, pinned via CMakeLists/3rdParty build files) to read these archives. In libmpq__file_number_from_hash (libmpq/mpq.c around line 740), the block_table_index taken from a hash-table entry is used to address the in-memory block/MPQ map without validating it against the table's actual element count, so an archive with an out-of-range index causes a heap out-of-bounds read (CWE-125) when the entry is resolved, and the resulting invalid access crashes the game. The patch reference is a DevilutionX pull request (8482) whose visible diff reworks third-party vendoring and build configuration - deleting the bundled 3rdParty/PKWare explode/implode sources and project files and touching .gitmodules - consistent with the project re-vendoring or updating its bundled archive-handling dependency rather than patching the call site in place; the trigger path is otherwise confined to hash/block-table lookups, so archives that never carry a malformed block_table_index are unaffected.

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Severity by source

Vendor (VulnCheck) PRIMARY 6.8 MEDIUM
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
vuln.today AI 5.5 MEDIUM

Local crafted-file vector loaded by the user (AV:L, UI:R), no auth needed (PR:N); out-of-bounds read only crashes the process, so A:H with C:N/I:N.

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
None
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

DevilutionX 1.4.0 through 1.5.5 contains an out-of-bounds read vulnerability in the bundled libmpq libmpq__file_number_from_hash function that allows attackers to read heap memory via unchecked block_table_index values. Attackers can place a crafted .mpq archive in the game's data path, such as a mod, to trigger reads past mpq_map and crash the game.

Threat Intelligence Overview

EPSS Score
0.1%
Top 98% exploitable
Prevalence
Low
open-source Diablo engine reimplementation; hobby game, no enterprise footprint
Social Media
1
Sightings
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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