# CVE-2026-29646: Privilege escalation in n/a

> A guest write to supervisor interrupt-enable CSR in OpenXiangShan NEMU with RVH enabled can corrupt machine-level interrupt state, breaking isolation.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Apr 2026
- **Updated:** 21 Apr 2026
- **Also known as:** GHSA-729m-5x6m-wwxv

## What is CVE-2026-29646?

CVE-2026-29646 is a critical vulnerability in n/a, published on 20 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In OpenXiangShan NEMU prior to 55295c4, when running with RVH (Hypervisor extension) enabled, a VS-mode guest write to the supervisor interrupt-enable CSR (sie) may be handled incorrectly and can influence machine-level interrupt enable state (mie). This breaks privilege/virtualization isolation and can lead to denial of service or privilege-boundary violation in environments relying on NEMU for correct interrupt virtualization.

Weakness: CWE-267 (Privilege Defined With Unsafe Actions)

## Which versions are affected by CVE-2026-29646?


## How do I fix CVE-2026-29646?

No fix has been published for CVE-2026-29646 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-29646 being exploited?

There is no known exploitation of CVE-2026-29646 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-29646 and fix it if it is affected.

What it is: CVE-2026-29646 is a critical vulnerability in n/a, published on 20 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-29646 in the wild and no public exploit code.

Affected product: n/a. 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-2026-29646/ (Markdown: https://insights.sbomify.com/CVE-2026-29646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-29646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29646
- OSV: https://osv.dev/vulnerability/CVE-2026-29646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-29646/
Summaries are generated and may contain mistakes; the official description above is the record.