CVE-2026-40959

Arbitrary code execution via unsanitized function environments

Published Apr 16, 2026 · Updated Apr 16, 2026

Sandbox escape in Luanti 5.0.0 through 5.15.1 allows local users to execute arbitrary code via a crafted mod when LuaJIT is used. The sandbox copies supposedly safe Lua functions without replacing their original environments, allowing getfenv to recover insecure globals. The flaw spans server-side, async, mapgen, and client-side mod contexts; exploitation grants full filesystem access under the Luanti process account.

CVSS severity9.3
Critical
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in Luanti 5.0.0 through 5.15.1 allows local users to execute arbitrary code via a crafted mod when LuaJIT is used. The sandbox copies supposedly safe Lua functions without replacing their original environments, allowing getfenv to recover insecure globals. The flaw spans server-side, async, mapgen, and client-side mod contexts; exploitation grants full filesystem access under the Luanti process account.

The record

CVE
CVE-2026-40959
Published
Apr 16, 2026
Updated
Apr 16, 2026
Vendor
Luanti
Product
Luanti
Classifications
CWE-829, T1059
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.0.0 <5.15.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Luanti · Luantiversion=5.0.0 <5.15.2

Published CVSS scores

9.3MITRECVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-829Inclusion of Functionality from Untrusted Control Sphere
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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