CVE intelligence and bounded remediation

CVE-2026-40317 — NovumOS is a custom 32-bit operating system written in Zig and x86 Assembly

Critical CVSS 9.3

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.

Severity
Critical
CVSS
9.3 (3.1)
Published
2026-04-18
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-20, CWE-269

Affected products

  • minecanton209 / novumos

Matched remediation archetype

Privilege escalation and unsafe privilege management

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
  • Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
  • Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

  • Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
  • Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
  • Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.

Authoritative sources

Complete CVE record and remediation plan

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