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Unreal Engine CVE-2026-14765

| EUVDEUVD-2026-100781 HIGH
Initialization of a Resource with an Insecure Default (CWE-1188)
2026-10-14 AHA GHSA-23f6-w88j-75xf
7.7
CVSS 3.1 · Vendor: AHA
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Attack ChainAIDerived

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

  1. Access
    Craft malicious Blueprint in UGC pack
  2. Delivery
    Victim loads content in UE game
  3. Exploit
    LaunchURL passes file:/// URI unfiltered
  4. Execution
    ShellExecuteW opens referenced executable
  5. Impact
    Arbitrary command execution on Windows host

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V13 - Configuration Secure default settings
Exploitation Conditions

Requires an Unreal Engine game or application (versions up to and including 5.8.0) that loads user-generated content containing Blueprints, running on Windows, with the default empty FURLRequestFilter (so all URL schemes, including file:///, are permitted). The attacker must deliver a malicious file either locally or via a WebDAV share, and the victim must load/interact with the malicious UGC (UI:R). Limiting factors that reduce real-world risk: Windows-only (depends on ShellExecuteW behavior), only affects titles that actually ingest third-party Blueprints, requires user interaction to load the content, and is rated high attack complexity; engines reconfigured with a non-empty scheme allowlist are not exploitable.

Impact

This is a genuine but conditionally-gated code-execution issue rather than a drop-everything internet-facing emergency. The provided CVSS 3.1 vector (AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H = 7.7 High) tells a consistent story: no privileges needed (PR:N), but the attack is local (AV:L), requires victim interaction (UI:R), and is of high complexity (AC:H), with a scope change (S:C) reflecting that a game-engine Blueprint pivots into OS-level command execution. There is a notable signal tension worth flagging: the description states the file can be delivered 'via a WebDAV share,' which sounds network-adjacent, yet the vector is scored AV:L - this is defensible because the malicious file must still be referenced and loaded by the engine through user-supplied content, but defenders should not read AV:L as 'requires attacker to already be on the box.' No EPSS score was supplied, so exploitation-probability cannot be quantified from the input. The CVE is not present in CISA KEV, so there is no confirmed active exploitation. No explicit POC flag was provided, though a third-party technical blog (khaelkugler.com) is referenced and may contain exploitation detail - treat exploit availability as unverified, not confirmed. Net: real priority for any title that loads user-generated Blueprint content on Windows (modding/UGC ecosystems), lower priority for engines/games that never ingest third-party Blueprints.

Exploit ScenarioDerived

An attacker publishes a malicious mod, map, or other user-generated content pack containing a Blueprint that calls LaunchURL with a file:/// URI (hosted locally or on an attacker-controlled WebDAV share). Because the default URL scheme filter is empty, a Windows victim who loads that content triggers ShellExecuteW with the open verb, executing the referenced file as arbitrary commands. A third-party technical write-up is referenced in the data, but no public exploit is confirmed in the provided intelligence.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 14, 2026

Code execution is possible in Epic Games Unreal Engine builds up to and including 5.8.0 on Windows because the LaunchURL Blueprint node (UKismetSystemLibrary::LaunchURL) ships with an empty FURLRequestFilter, allowing every URL scheme - including file:/// - to pass through to ShellExecuteW() with the open verb, which executes the referenced file. The issue is reachable only in titles that ingest user-generated content containing Blueprints: the attacker must supply a malicious file locally or via a WebDAV share and the victim must load or interact with that content (unauthenticated remote/local attacker, CVSS 3.1 base 7.7, AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H). No public exploit code has been identified at time of analysis; real-world risk is conditionally gated by the Windows-only dependency, the requirement that a game actually loads third-party Blueprints, mandatory user interaction, and high attack complexity.

RemediationAI

No vendor-released patch was identified in the provided data at time of analysis, so remediation currently rests on configuration and build-level controls. The most direct mitigation is to ship or rebuild the engine with a non-empty FURLRequestFilter scheme allowlist (for example permitting only https:// and disabling file://, ms-*, and other handler-bearing schemes), which removes the primitive entirely but requires source-level engine changes and a recompiled binary, and will break any intended file- or custom-protocol launching. Where engine modification is not feasible, disable or avoid the LaunchURL Blueprint node in shipped content and block games from loading untrusted Blueprints or UGC bundles - a strong control that trades away modding and community-content functionality. On the deployment side, block outbound access to WebDAV/UNC paths from game processes and restrict which local files a title can reference, accepting that this only raises attacker effort rather than fixing the root cause. Running affected titles under a low-privilege account or sandbox reduces the value of execution, with the trade-off of potential breakage for legitimate game functionality. Monitor the Epic Games advisory channel and the researcher writeup at https://khaelkugler.com/blogs/meccha_chameleon.html plus the GCVE record at https://takeonme.org/gcves/GCVE-1337-2026-00000000000000000000000000000000000000000000000001011111111101111111111110000000000000000000000000000000000000000000000000000001011 for a vendor fix; no patched version number can be cited from current data.

Affected VersionsENISA

Unreal Engine 0 ≤5.8.0

Affected Packages

euvd unreal_engine 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

The defect is a CWE-1188 insecure-default initialization inside Unreal Engine's Blueprint-facing system library. UKismetSystemLibrary::LaunchURL delegates URL handling to FURLRequestFilter, which is intended to enforce a scheme allowlist; shipped with an empty filter, the check permits all schemes rather than denying-by-default. On Windows the node ultimately calls ShellExecuteW() with the "open" verb, and because ShellExecuteW resolves file:/// URIs to local executables, a crafted URI yields code execution in the game process context. Access vectors include a malicious local file already present on disk or a file reachable over a WebDAV share, both of which can be supplied through user-generated content that carries Blueprints. The CPE entry cpe:2.3:a:epic_games:unreal_engine:*:*:*:*:*:*:*:* covers the affected product line without a version delimiter, consistent with the advisory scope of "all versions up to and including 5.8.0". Third-party metadata tags this item under Information Disclosure, Microsoft, and Unreal Engine; the independently assessed impact is local-user-context code execution with scope change, not merely disclosure. Instances are derived from the researcher writeup at khaelkugler.com and the GCVE record referenced at takeonme.org.

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Severity by source

Vendor (AHA) PRIMARY 7.7 HIGH
AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
vuln.today AI 7.7 HIGH

Malicious content must be loaded locally with victim interaction (AV:L/UI:R), delivery/WebDAV setup makes it AC:H, no auth (PR:N), and engine-to-OS command execution gives S:C with full C:H/I:H/A:H.

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

Primary rating from Vendor (AHA).

CVSS VectorVendor: AHA

Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Epic Games Unreal Engine versions up to and including 5.8.0 ship with an insecure default configuration for the LaunchURL Blueprint node (UKismetSystemLibrary::LaunchURL). The URL scheme filter (FURLRequestFilter) is empty by default, which permits all URL schemes. On Windows, this results in a call to ShellExecuteW() with the open verb, so a supplied file:/// URI causes the referenced file to be executed. Any Unreal Engine game that loads user-generated content containing Blueprints is vulnerable to command execution via a malicious local file or a remote file on a WebDAV share. This is an instance of CWE-1188 (Initialization of a Resource with an Insecure Default).

Executive ViewAI

Why It Matters

A high-severity code execution flaw affects Epic Games Unreal Engine builds through version 5.8.0 on Windows, allowing a crafted file to run arbitrary code on a player's or developer's machine whenever it is opened through the engine's URL-handling Blueprint. Exposure is limited to organizations that build or operate Windows-based Unreal titles which load third-party or user-generated Blueprints, such as modding platforms, marketplace-driven games, and internal development workstations, where a single opened asset could compromise the host. Because no vendor patch is available and the flaw is unauthenticated but requires user interaction and a high-complexity delivery chain, leadership should treat this as a manageable but unresolved supply-chain risk requiring interim hardening rather than emergency shutdown.

Business Impact: Medium
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: disable or remove the LaunchURL (UKismetSystemLibrary::LaunchURL) Blueprint node from affected titles and replace it with a hardened wrapper that enforces a strict URL scheme allow-list rejecting file:/// (and other non-web schemes); block WebDAV/WebClient on endpoints and build hosts to cut off the remote delivery path; require signed, vetted Blueprints and prohibit loading untrusted user-generated content; run Unreal builds that consume third-party content in a sandboxed or containerized environment with no host file-share access; and apply least-privilege execution plus application control on Windows hosts running the engine while awaiting a fixed release from Epic Games.

Threat Intelligence Overview

EPSS Score
0.4%
Top 69% exploitable
Prevalence
High
one of two dominant commercial game engines, very widely shipped
Social Media
1
Sightings
Data Quality
4 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 HIGH
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Medium

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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

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