Is CVE-2026-40959 in the CISA KEV catalog?

No. CVE-2026-40959 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-40959?

CVE-2026-40959 has a CVSS v3 base score of 9.3 (CRITICAL).

What is the EPSS score for CVE-2026-40959?

CVE-2026-40959 has an EPSS score of 0.18% (8th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40959?

Upgrade luanti on debian 13 to 5.10.0+dfsg-5+deb13u1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2026-40959

CRITICAL

9.3

CVSS v3

NVD

Description

Luanti 5 before 5.15.2, when LuaJIT is used, allows a Lua sandbox escape via a crafted mod.

CWE-829

How to fix

Remediation Available

luantiDebian

Fixed in:5.10.0+dfsg-5+deb13u1CVE-2026-40959

Fixed in:5.15.2+dfsg-1CVE-2026-40959

luantiUbuntu

Fixed in:5.10.0+dfsg-5+deb13u1build0.25.10.1USN-8366-1

luanti-dataUbuntu

Fixed in:5.10.0+dfsg-5+deb13u1build0.25.10.1USN-8366-1

luanti-serverUbuntu

Fixed in:5.10.0+dfsg-5+deb13u1build0.25.10.1USN-8366-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.18%probability of exploitation in 30 days

8thpercentile

Low risk: more likely to be exploited than 8% of all known CVEs.

References

Other references3

Related Vulnerabilities

Other CWE-829 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2018-17246	Critical	9.8	82%	-	Fix
CVE-2024-5762	High	8.1	72%	-	-
CVE-2018-7422	High	7.5	63%	-	-
CVE-2023-2249	High	8.8	61%	-	-
CVE-2025-32463	Critical	9.3	47%	KEV	Fix
CVE-2024-38476	Critical	9.8	42%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-19.