CVE-2026-40317

Critical

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.

SeverityCritical
CVSS9.3
Exploit probability—
ProductMinecanton209 Novumos
PublishedApr 18, 2026
First seenApr 18, 2026

How to fix

Update
  • minecanton209 novumos0.24 or later

Affected products

ProductAffected versionsFixed in
minecanton209 novumosv < 0.240.24

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