How severe is CVE-2026-40317?

CVE-2026-40317 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-40317 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40317?

CVE-2026-40317 affects Minecanton209 Novumos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40317?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-40317 have an EU (EUVD) identifier?

Yes. CVE-2026-40317 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23630.

When was CVE-2026-40317 published?

CVE-2026-40317 was published on 2026-04-18 and last updated on 2026-06-17.

CVE-2026-40317

CVE-2026-40317 is a critical-severity vulnerability in Minecanton209 Novumos with a CVSS 3.x base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23630
Weakness: CWE-20
Affected product: Minecanton209 Novumos
Published: 2026-04-18
Last modified: 2026-06-17

Description

NovumOS is a custom 32-bit operating system written in Zig and x86 Assembly. In versions prior to 0.24, Syscall 12 (JumpToUser) accepts an arbitrary entry point address from user-space registers without validation, allowing any Ring 3 user-mode process to jump to kernel addresses and execute arbitrary code in Ring 0 context, resulting in local privilege escalation. This issue has been fixed in version 0.24. If developers are unable to immediately update, they should restrict syscall access by running the system in single-user mode without Ring 3, and disable user-mode processes by only running kernel shell with no user processes. This issue has been fixed in version 0.24.

Frequently asked questions

What is CVE-2026-40317?: NovumOS is a custom 32-bit operating system written in Zig and x86 Assembly. In versions prior to 0.24, Syscall 12 (JumpToUser) accepts an arbitrary entry point address from user-space registers without validation, allowing any Ring 3 user-mode process to jump to kernel addresses and execute arbitrary code in Ring 0 context, resulting in local privilege escalation. This issue has been fixed in version 0.24. If developers are unable to immediately update, they should restrict syscall access by running the system in single-user mode without Ring 3, and disable user-mode processes by only running kernel shell with no user processes. This issue has been fixed in version 0.24.
How severe is CVE-2026-40317?: CVE-2026-40317 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-40317 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40317?: CVE-2026-40317 affects Minecanton209 Novumos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40317?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-40317 have an EU (EUVD) identifier?: Yes. CVE-2026-40317 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23630.
When was CVE-2026-40317 published?: CVE-2026-40317 was published on 2026-04-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:minecanton209:novumos:*:*:*:*:*:*:*:*

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