🛡️ CVE-2026-40317 — novumos

🔴 CVSS 9.3 — Critical ⚠️ Exploit Public CWE-20 NVD
9.3
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-40317 is classified as CWE-20: Improper Input Validation. The application accepts input without checking that it has the expected form, so malformed values reach code that assumes they are well formed.

Affected software

CVE-2026-40317 is recorded against 1 package.

  • novumos (fixed in 0.24)

Timeline and source

Published on 18 April 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
github.com
github.com

Details

Severity CRITICAL
CVSS Score 9.3
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CWE CWE-20
Public Exploit ⚠️ Yes
Source NVD
Published 2026-04-18
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
novumos — 0.24

Similar Threats

Exploit Protection

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CVE-2026-40317 carries CVSS 9.3 Critical rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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