# OSV-2021-1230: UNKNOWN READ in helper_ret_stb_mmu_x86_64

> An unknown read vulnerability in QEMU's x86_64 helper function can cause a crash, potentially leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Sep 2021

## What is OSV-2021-1230?

OSV-2021-1230 is a memory corruption vulnerability in unicorn, published on 12 Sep 2021. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=38438

```
Crash type: UNKNOWN READ
Crash state:
helper_ret_stb_mmu_x86_64
resume_all_vcpus_x86_64
vm_start_x86_64
```

## Which versions are affected by OSV-2021-1230?

1 open source package ship an affected version, including unicorn.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `unicorn` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2021-1230?

No fix has been published for OSV-2021-1230 yet. Limit exposure of the affected software until one is available.

## Is OSV-2021-1230 being exploited?

There is no known exploitation of OSV-2021-1230 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2021-1230 and fix it if it is affected.

What it is: OSV-2021-1230 is a memory corruption vulnerability in unicorn, published on 12 Sep 2021. 
Exploitation: There is no known exploitation of OSV-2021-1230 in the wild and no public exploit code.

Affected packages and fixed versions:
- unicorn (OSS-Fuzz): affected all versions; no fix listed

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/OSV-2021-1230/ (Markdown: https://insights.sbomify.com/OSV-2021-1230/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2021-1230

---
From sbomify Insights: https://insights.sbomify.com/OSV-2021-1230/
Summaries are generated and may contain mistakes; the official description above is the record.