# CVE-2026-29649: Other in n/a

> A flaw in NEMU's RISC-V Hypervisor CSR handling allows machine-mode writes to incorrectly modify hypervisor configuration, potentially causing denial of service.

- **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-p786-pp8p-8p3m

## What is CVE-2026-29649?

CVE-2026-29649 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

NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-29649?

It affects 1 product.


Products: Xiangshan Nemu.

## How do I fix CVE-2026-29649?

No fix has been published for CVE-2026-29649 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-29649 being exploited?

There is no known exploitation of CVE-2026-29649 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-29645](https://insights.sbomify.com/CVE-2026-29645/): Other in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-29649 and fix it if it is affected.

What it is: CVE-2026-29649 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-2026-29649 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-2026-29649/ (Markdown: https://insights.sbomify.com/CVE-2026-29649/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-29649
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29649
- OSV: https://osv.dev/vulnerability/CVE-2026-29649

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-29649/
Summaries are generated and may contain mistakes; the official description above is the record.