# CVE-2026-40317: NovumOS has Privilege Escalation in the Syscall Interface

> A local attacker can escalate privileges to Ring 0 by exploiting unvalidated syscall entry points in NovumOS, allowing arbitrary kernel code execution.

- **Severity:** Critical 9.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Apr 2026
- **Updated:** 20 Apr 2026
- **Also known as:** GHSA-xjx3-gjh9-45fm

## What is CVE-2026-40317?

CVE-2026-40317 is a critical vulnerability in MinecAnton209 NovumOS, published on 18 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-269 (Improper Privilege Management), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-40317?

It affects 1 product.


Products: Minecanton209 Novumos.

## How do I fix CVE-2026-40317?

No fix has been published for CVE-2026-40317 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40317 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40317 exists.

## Other vulnerabilities in MinecAnton209 NovumOS

- [CVE-2026-40572](https://insights.sbomify.com/CVE-2026-40572/): NovumOS has Arbitrary Memory Mapping via Syscall 15 (MemoryMapRange) (critical 9.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40317 and fix it if it is affected.

What it is: CVE-2026-40317 is a critical vulnerability in MinecAnton209 NovumOS, published on 18 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40317 exists.

Affected product: MinecAnton209 NovumOS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40317/ (Markdown: https://insights.sbomify.com/CVE-2026-40317/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40317
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40317
- OSV: https://osv.dev/vulnerability/CVE-2026-40317

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40317/
Summaries are generated and may contain mistakes; the official description above is the record.