# OSV-2023-280: Heap-use-after-free in mrb_str_hash_m

> A heap-use-after-free vulnerability in the mruby string hashing function allows attackers to potentially execute arbitrary code or cause a 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:** 5 Apr 2023

## What is OSV-2023-280?

OSV-2023-280 is an use after free vulnerability in mruby, published on 5 Apr 2023. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=57672

```
Crash type: Heap-use-after-free READ 1
Crash state:
mrb_str_hash_m
mrb_vm_exec
mrb_vm_run
```

## Which versions are affected by OSV-2023-280?

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


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

## How do I fix OSV-2023-280?

No fix has been published for OSV-2023-280 yet. Limit exposure of the affected software until one is available.

## Is OSV-2023-280 being exploited?

There is no known exploitation of OSV-2023-280 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2023-280 and fix it if it is affected.

What it is: OSV-2023-280 is an use after free vulnerability in mruby, published on 5 Apr 2023. 
Exploitation: There is no known exploitation of OSV-2023-280 in the wild and no public exploit code.

Affected packages and fixed versions:
- mruby (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-2023-280/ (Markdown: https://insights.sbomify.com/OSV-2023-280/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2023-280

---
From sbomify Insights: https://insights.sbomify.com/OSV-2023-280/
Summaries are generated and may contain mistakes; the official description above is the record.